John Copeland, et al. v. Cyrus R. Vance, Jr. Southern District of New York - New York, New York

Plaintiffs‐appellants John Copeland, Pedro Perez, and Native Leather, Ltd.

(collectively, “plaintiffs”) appeal from a judgment against them following a

bench trial in the United States District Court for the Southern District of New

York (Forrest, J.). Plaintiffs claim that New York’s ban on gravity knives is void

for vagueness under the Due Process Clause of the Fourteenth Amendment as

applied to “[k]nives that are designed to resist opening from their folded and

closed position,” or common folding knives. J. App’x 51. New York law defines a

gravity knife as a knife that can be opened to a locked position with a onehanded

flick of the wrist. Plaintiffs mainly argue that the statute cannot lawfully

be applied to common folding knives because the wrist‐flick test is so

indeterminate that ordinary people cannot reliably identify legal knives.

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Key to deciding this case is determining whether the plaintiffs’ vagueness

claim should be understood as an as‐applied challenge or a facial challenge.

Because plaintiffs’ claim would, if successful, effectively preclude all

enforcement of the statute, and because plaintiffs sought to prove their claim

chiefly with hypothetical examples of unfair prosecutions that are divorced from

their individual facts and circumstances, we deem it a facial challenge. Plaintiffs

therefore must show that the gravity knife law is invalid in all applications,

including as it was enforced against them in three prior proceedings. Under this

strict standard, the challengers’ claim will fail if the gravity knife law was

constitutionally applied to any one of the challengers. We conclude that Native

Leather did not carry its burden. Accordingly, we affirm the judgment of the

district court.

BACKGROUND

The State of New York prohibits the possession of a “gravity knife,” which

is defined as “any knife which has a blade which is released from the handle or

sheath thereof by the force of gravity or the application of centrifugal force

which, when released, is locked in place by means of a button, spring, lever or

other device.” N.Y. Penal Law §§ 265.01(1), 265.00(5) (”gravity knife law”). The

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law, originally passed in 1958, remains unchanged today.1 The gravity knife law

employs a functional, rather than design‐based, definition. A knife is a gravity

knife if it operates as one—the blade must “release[] from the handle” by gravity

or by “the application of centrifugal force” and then “lock[] in place”—even if

the manufacturer did not design it to do so. Id. § 265.00(5); see People v. Neal, 913

N.Y.S.2d 192, 194 (1st Dep’t 2010) (finding proof sufficient where “[t]he officer

demonstrated in court that he could open the knife by using centrifugal force,

created by flicking his wrist, and the blade automatically locked in place after

being released”). Some other banned weapons are defined by their design. See,

e.g., N.Y. Penal Law § 265.00(15‐b) (“‘Kung Fu star’ means a disc‐like object with

sharpened points on the circumference thereof and is designed for use primarily

as a weapon to be thrown.”).

Knowledge that a knife responds to the wrist‐flick test is not an element of

this crime. See People v. Parrilla, 27 N.Y.3d 400, 402 (2016) (“[T]he mens rea

prescribed by the legislature for criminal possession of a gravity knife simply

1 At least for now. The Governor of New York recently vetoed two attempts to

amend the gravity knife law, one of which would have used a design‐based definition,

and the other of which would have eliminated the centrifugal force clause.

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requires a defendant’s knowing possession of a knife, not knowledge that the

knife meets the statutory definition of a gravity knife.”). Possessing a gravity

knife is a misdemeanor offense, but it can be charged as a felony if the offender

has previously been convicted of a crime. See id. at 404 & n.2.

To determine whether a knife is a gravity knife, police officers and

prosecutors “us[e] the force of a one‐handed flick‐of‐the‐wrist to determine

whether a knife will open from a closed position,” a method known as the wristflick

test. Copeland v. Vance, 230 F. Supp. 3d 232, 238 (S.D.N.Y. 2017). Officers are

trained in the wrist‐flick test at the Police Academy, and each of the officers

involved in the events giving rise to this case received this training. “[A]rrests

and prosecutions for possession of a gravity knife only occur once a knife has

opened in response to the Wrist‐Flick test.” Id. at 242. “[T]he same Wrist‐Flick

test has been used by the NYPD to identify gravity knives since the statute’s

effective date” and continuing to the present. Id. The district court found that

“the evidence supports a known, consistent functional test for determining

whether a knife fits the definition of a ‘gravity knife’ and does not support

inconsistent outcomes under that test.” Id.

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John Copeland is an artist who lives in Manhattan. In the fall of 2009,

Copeland bought a folding knife at a Manhattan retailer and asked two police

officers whether the knife was legal. When neither officer could open the knife

with the wrist‐flick test, they told him it was. Copeland regularly used the knife

over the next year. In October 2010, two police officers stopped Copeland when

they saw the knife clipped to his pocket. One of the officers applied the wristflick

test, and the knife fully opened to a locked position on the first attempt.

Copeland was arrested and charged with violating the gravity knife law. He later

agreed to an adjournment in contemplation of dismissal of the charge.

Pedro Perez is an art dealer who also lives in Manhattan. In April 2008,

Perez bought a folding knife from a Manhattan retailer, and he regularly used

the knife to cut canvas and open packaging. On April 15, 2010, three police

officers stopped Perez in a subway station when they observed the knife clipped

to his pants pocket. One of the officers applied the wrist‐flick test, and the knife

fully opened to a locked position on the first attempt. Perez was arrested and

charged with violating the gravity knife law. Perez did not contest the charge,

accepted an adjournment in contemplation of dismissal, and agreed to perform

seven days of community service.

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Native Leather, Ltd. is a Manhattan‐based retailer that sells folding knives.

In 2010, investigators from the office of the New York County District Attorney

(“D.A.”) determined that some of Native Leather’s knives could be opened with

the wrist‐flick test and issued a subpoena requiring Native Leather to produce

any gravity knives in its inventory. Carol Walsh, the owner and president of

Native Leather, produced over 300 knives that she thought were gravity knives.

The D.A.’s office tested each knife, retained any that could be opened with the

wrist‐flick test at least one time in ten attempts, and returned the balance. On

June 15, 2010, Native Leather entered a deferred prosecution agreement under

which it agreed to test its inventory for gravity knives and to submit to

inspections by an independent monitor. Walsh began testing Native Leather’s

knives in September 2010 and would not offer a knife for sale if she could flick it

open or if she believed a “stocky man” would be able to. Id. at 244 (brackets

omitted).

On September 24, 2012, Copeland, Perez, and Native Leather, along with

Knife Rights, Inc. and Knife Rights Foundation, Inc., filed an amended complaint

against defendants‐appellees D.A. Cyrus R. Vance, Jr. and the City of New York

challenging the gravity knife law as void for vagueness. Plaintiffs divide gravity

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knives into two categories that are not recognized by the statute or case law, but

are, they maintain, recognized by the knife industry: the “true gravity knife” and

the “common folding knife.” True gravity knives, in their view, can be opened by

the force of gravity alone (although they also respond to the wrist‐flick test). As

the blade will slide freely out of the handle, this knife is said to lack a bias toward

closure. Plaintiffs’ paradigmatic true gravity knife is the formidable‐sounding

“German paratrooper knife.” True gravity knives appear to be quite rare.

Plaintiffs assert that no domestic manufacturer produces them, and multiple

policer officers with significant experience enforcing the gravity knife law

declared that they have never encountered one. Plaintiffs concede that true

gravity knives can constitutionally be banned.

Plaintiffs’ vagueness challenge focuses instead on common folding knives,

which, they explain, are knives that are designed to have a bias toward closure.

These knives resist opening. They cannot be opened by gravity alone; some

additional force must be applied. This category includes folding knives openly

sold and owned by many law‐abiding people. It also includes the knives

plaintiffs carried and sold in 2010. The plaintiffs wish to carry (and, in Native

Leather’s case, sell) common folding knives again, but claim that they cannot

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determine which knives are legal. They seek a declaration that the gravity knife

law is void for vagueness “as applied to Common Folding Knives” and an

injunction restraining the defendants from enforcing the gravity knife law “as to

Common Folding Knives.” J. App’x 51–52.

On September 25, 2013, the district court dismissed the complaint for lack

of standing. We affirmed as to the knife advocacy organizations, but held that

Copeland, Perez, and Native Leather have standing. Knife Rights, Inc. v. Vance,

802 F.3d 377, 379 (2d Cir. 2015). On remand, the district court conducted a bench

trial and held an in‐court knife demonstration. Following these proceedings, the

district court, based on the findings of fact recounted above, rejected plaintiffs’

vagueness claim. The district court concluded that the gravity knife law was

constitutionally applied to Copeland, Perez, and Native Leather during the

enforcement actions that took place in 2010 (the “2010 enforcement actions”) and

that it would continue to be constitutionally applied to them prospectively. The

district court then concluded that, to the extent plaintiffs’ claim could be

understood as a facial attack on the gravity knife law, it was unsuccessful. This

appeal followed.

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DISCUSSION

I. Standard of Review

“On appeal from a bench trial, we review findings of fact for clear error

and conclusions of law de novo.” Fed. Hous. Fin. Agency for Fed. Nat’l Mortg. Ass’n

v. Nomura Holding Am., Inc., 873 F.3d 85, 138 n.54 (2d Cir. 2017). “Under the clear

error standard, factual findings by the district court will not be upset unless we

are left with the definite and firm conviction that a mistake has been committed.”

Id. (brackets omitted) (quoting Henry v. Champlain Enters., Inc., 445 F.3d 610, 617

(2d Cir. 2006)).

II. Classifying Plaintiffs’ Vagueness Challenge

The first issue on appeal is whether, as the district court held, plaintiffs

have the burden to show that the gravity knife law was void for vagueness as

applied to them in the 2010 enforcement actions. We conclude that they do.

The Fourteenth Amendment provides that no state shall “deprive any

person of life, liberty, or property, without due process of law.” U.S. Const.

amend. XIV, § 1. A component of the Due Process Clause, “the void‐forvagueness

doctrine requires that a penal statute define the criminal offense with

sufficient definiteness that ordinary people can understand what conduct is

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prohibited and in a manner that does not encourage arbitrary and discriminatory

enforcement.” Kolender v. Lawson, 461 U.S. 352, 357 (1983). In any vagueness case,

then, the challenger can prevail by showing that the statute either “fails to

provide people of ordinary intelligence a reasonable opportunity to understand

what conduct it prohibits” or “authorizes or even encourages arbitrary and

discriminatory enforcement.” Hill v. Colorado, 530 U.S. 703, 732 (2000).

A party challenging a statute as void for vagueness must normally show

that any prior enforcement action against the challenger was unconstitutional.

That is the essence of an ordinary “as‐applied” claim, in which the challenger

asserts that a law cannot constitutionally be applied to the challenger’s

individual circumstances. The claim is typically that the statute provided

insufficient notice that her conduct was illegal. See, e.g., Dickerson v. Napolitano,

604 F.3d 732, 745 (2d Cir. 2010) (“A plaintiff making an as‐applied challenge

must show that the statute in question provided insufficient notice that his or her

behavior at issue was prohibited.”). As‐applied challenges are often raised as

defenses to individual prosecutions. See, e.g., United States v. Nadi, 996 F.2d 548

(2d Cir. 1993).

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A statute may also be challenged as vague “on its face.” The claim in a

facial challenge is that a statute is so fatally indefinite that it cannot

constitutionally be applied to anyone. A facial challenge is “the most difficult

challenge to mount successfully” because, as a general matter, “the challenger

must establish that no set of circumstances exists under which the Act would be

valid.” United States v. Salerno, 481 U.S. 739, 745 (1987); accord Hoffman Estates v.

Flipside, 455 U.S. 489, 495 (1982) (explaining that an ordinary facial challenge will

succeed “only if the enactment is impermissibly vague in all of its

applications”).2

Because this standard is so comprehensive, a facial challenger must show

that every prior enforcement action against her was unconstitutional. See Holder

v. Humanitarian Law Project, 561 U.S. 1, 18–19 (2010) (“We consider whether a

statute is vague as applied to the particular facts at issue, for ‘[a] plaintiff who

2 These general principles are more flexible in vagueness cases involving the First

Amendment or fundamental rights. See Farrell v. Burke, 449 F.3d 470, 496 (2d Cir. 2006).

In addition, in certain exceptional circumstances not present here, a criminal statute

may be struck down as facially vague even where it has some valid applications. See

Johnson v. United States, 135 S. Ct. 2551, 2557–60 (2015) (invalidating provision that

required courts to imagine an ordinary version of a crime and assess whether such

idealized conduct implied some degree of risk); Sessions v. Dimaya, 138 S. Ct. 1204, 1213–

16 (2018) (same).

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engages in some conduct that is clearly proscribed cannot complain of the

vagueness of the law as applied to the conduct of others.’” (quoting Flipside, 455

U.S. at 495)). If a court concludes that a statute was constitutionally applied to a

facial challenger, then it generally need not consider the statute’s applicability in

other situations. See Diaz v. Paterson, 547 F.3d 88, 101 (2d Cir. 2008) (“Because

plaintiffs have failed to plead facts establishing that Article 65 is unconstitutional

as applied to them, they necessarily fail to state a facial challenge . . . .”). Facial

claims are “disfavored” because they “often rest on speculation,” flout the

“fundamental principle of judicial restraint” that courts should avoid

unnecessary constitutional adjudication, Wash. State Grange v. Wash. State

Republican Party, 552 U.S. 442, 450 (2008), and “threaten to short circuit the

democratic process,” id. at 451.

Not all proponents of a vagueness challenge must show the infirmity of a

prior enforcement action, however. A statute can be attacked as vague before it

has been enforced against the challenger, see, e.g., N.Y. State Rifle & Pistol Ass’n v.

Cuomo, 804 F.3d 242, 265 (2d Cir. 2015), and a party asserting a pre‐enforcement

challenge obviously cannot be required to show that a prior action was invalid.

And although the matter is not entirely settled, the proponent of a facial

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vagueness claim may not need to show that a statute was unconstitutionally

applied to the challenger if the statute “reaches ‘a substantial amount of

constitutionally protected conduct,’” particularly rights protected by the First

Amendment. Kolender, 461 U.S. at 358–59 n.8 (quoting Flipside, 455 U.S. at 494);

accord City of Chicago v. Morales, 527 U.S. 41, 60–64 (1999) (facially invalidating a

city ordinance without examining whether it was unconstitutionally applied to

the challengers); Farrell, 449 F.3d at 496 (explaining that “[w]hen fundamental

rights are implicated,” a defendant to whom a statute was constitutionally

applied may nonetheless “‘raise its vagueness . . . as applied to others’” (quoting

Coates v. City of Cincinnati, 402 U.S. 611, 620 (1971))). Neither of these principles

has any application here. As recounted above, the gravity knife law was

previously enforced against each of the three plaintiffs, and no claim is made that

the statute infringes fundamental rights.

Plaintiffs instead argue that they need not show that the 2010 enforcement

actions were unconstitutional because they bring an as‐applied challenge that

seeks only prospective relief. According to the plaintiffs, they need not prove

that the 2010 enforcement actions were unconstitutional because they do not seek

any relief from those proceedings (such as, for example, nullification of Native

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Leather’s deferred prosecution agreement). They instead seek prospective relief

that would allow them to own folding knives without fear of future prosecution

under the gravity knife law.

Courts consider prospective, as‐applied vagueness challenges

comparatively infrequently. Unlike the ordinary as‐applied challenge, where the

claim is that a prior enforcement action was invalid, a prospective as‐applied

challenge seeks to prove that a statute cannot constitutionally be applied to a

specific course of conduct that the challenger intends to follow. A recent

Supreme Court case is instructive. In Expressions Hair Design v. Schneiderman, the

Supreme Court considered a vagueness challenge to New York’s credit card

surcharge ban, which provides that “[n]o seller in any sales transaction may

impose a surcharge on a holder who elects to use a credit card in lieu of payment

by cash, check, or similar means.” 137 S. Ct. 1144, 1147 (2017) (quoting N.Y. Gen.

Bus. Law § 518). The statute had been enforced only rarely, see id. at 1154 n.2

(Sotomayor, J., concurring in the judgment), and never against the plaintiffs.

Before the Supreme Court, the plaintiffs argued that this law would be

unconstitutional if applied to a single scheme of pricing they wished to employ:

“posting a cash price and an additional credit card surcharge.” Id. at 1149. The

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Court framed this as an “as‐applied challenge” of “narrow scope,” id. at 1149 n.1,

and, concluding that “it is at least clear that § 518 proscribes their intended

speech,” rejected the vagueness challenge, id. at 1152 (emphasis added).

We agree in principle that someone who intends to engage in a course of

conduct that differs from the conduct that gave rise to a prior enforcement action

against her should be relieved of the burden to show that the prior proceeding

was invalid. That a statute was lawfully applied to one set of facts does not

necessarily prove that it may lawfully be applied to a different set of facts. More

concretely, we think that someone previously convicted for carrying what is

indisputably a gravity knife should be permitted to claim that the gravity knife

law cannot lawfully be applied to a different knife that she intends to carry and

that responds differently to the wrist‐flick test.

But plaintiffs have not asserted a prospective, as‐applied challenge. Unlike

the “narrow” challenge to New York’s credit card surcharge ban, id. at 1149 n.1,

the claim here is for exceedingly broad relief—indeed, so broad that plaintiffs

concede it could be seen a species of facial challenge. Plaintiffs seek, not a

declaration that the statute cannot be applied to certain knives they wish to

personally carry, but a declaration that the statute cannot constitutionally be

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applied to anyone carrying any knife in the very large “common folding knife”

category. The evidence shows that the gravity knife law has for decades been

enforced mainly, and perhaps exclusively, against such knives. As a

consequence, and as plaintiffs conceded at oral argument, their vagueness

challenge would, if successful, disable the entire statute. The challenge thus more

resembles a facial challenge than an as‐applied challenge.

Plaintiffs’ manner of proof also shows that their claim is not a prospective

as‐applied challenge, but a challenge to the gravity knife law on its face. A party

asserting a prospective as‐applied challenge must tailor the proof to the specific

conduct that she would pursue but for fear of future enforcement. See VIP of

Berlin, LLC v. Town of Berlin, 593 F.3d 179, 189 (2d Cir. 2010) (“[I]n the context of

an as‐applied vagueness challenge, a court’s analysis should be confined to the

litigant’s actual conduct, and a court should not analyze whether a reasonable

person would understand that certain hypothetical conduct or situations violate

the statute.”). The challenger cannot instead rely on hypothetical situations in

which the statute could not validly be applied. In Expressions Hair Design, for

example, the plaintiffs offered a “wide array of hypothetical pricing regimes,”

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but the Supreme Court “limit[ed] . . . review” to the “one pricing scheme

[plaintiffs sought] to employ.” 137 S. Ct. at 1149.

If this were a true prospective as‐applied challenge, we would therefore

expect plaintiffs to have offered proof that specific knives they wished to possess

responded inconsistently, if at all, to the wrist‐flick test. They did not. Plaintiffs

instead seek to show that the gravity knife law is vague by positing hypothetical

unfair enforcement actions in which the statute could not be constitutionally

applied. For example, they invite us to consider the prosecution of someone who,

after attempting to flick open a knife several times, concludes that it is legal and

purchases it, only to be immediately stopped by an officer who succeeds in

flicking it open. This type of “proof” is simply not cognizable in an as‐applied

challenge. See id. It may, however, be entertained in a facial challenge. See Farrell,

449 F.3d at 496.

To be sure, plaintiffs label their challenge “as applied,” and, in a bid to

avoid the rule that a statute is not vague on its face unless it is vague in all

applications, disclaim a full‐fledged facial challenge. But plaintiffs use the term

“as applied” in an idiosyncratic way. They do not mean that the statute cannot

lawfully be applied to their personal facts and circumstances, but that the statute

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cannot lawfully be applied to a broad class of knives that could be carried by

anyone. Cf. Dickerson, 604 F.3d at 745 (“To successfully make an as‐applied

vagueness challenge, the plaintiffs must show that section 14–107 either failed to

provide them with notice that possession of their badges was prohibited or failed

to limit sufficiently the discretion of the officers who arrested them under the

statute.”). The sweeping relief sought and the method of proof advanced

persuade us that this is a facial challenge.

And so we reject plaintiffs’ contention that they need not show that the

gravity knife law was unconstitutionally applied to them in 2010. As plaintiffs

conceded below, in an ordinary facial vagueness claim, the challenger must show

that the statute is invalid in all respects. See Salerno, 481 U.S. at 745. When the

enactment has been previously applied to a facial challenger, a court should first

evaluate the claim as applied to the challenger’s facts and circumstances, see

Rubin v. Garvin, 544 F.3d 461, 468–69 (2d Cir. 2008), and if the statute was

constitutionally applied to the challenger, then the vagueness claim fails, see

Flipside, 455 U.S. at 494–95; Diaz, 547 F.3d at 101. Accordingly, plaintiffs can

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prevail on their vagueness claim only if they show that the statute was vague as

applied to them in the 2010 enforcement actions.3

III. Whether the Gravity Knife Law Was Constitutionally Enforced Against

the Plaintiffs

The district court held that the plaintiffs did not show that the gravity

knife statute was unconstitutionally applied to them in 2010. On appeal,

plaintiffs do little to directly confront this holding, relying primarily on more

general contentions that the statute provides insufficient notice of which knives

are legal. We conclude that the gravity knife law was constitutionally enforced

against at least one of the plaintiffs in 2010.4

3 Plaintiffs, relying on Dimaya, 138 S. Ct. 1204, decided after this appeal was

heard, argue that a statute must be clear in all its applications to survive a vagueness

challenge. This gets the rule backward. Under a long line of decisions that Dimaya did

not disturb, a statute will generally survive a facial challenge so long as it is not invalid

in all its applications. See, e.g., Salerno, 481 U.S. at 745; Flipside, 455 U.S. at 494–95. That is

the rule we apply here.

4 We observe that the defendants do not argue that plaintiffs’ concession that the

statute can validly be applied to true gravity knives dooms their entire claim. Cf. N.Y.

State Rifle & Pistol Ass’n, 804 F.3d at 265 (“[T]o succeed on a facial challenge, the

challenger must establish that no set of circumstances exists under which the Act would

be valid.” (internal quotation marks omitted)). Defendants instead meet plaintiffs’

vagueness challenge as advanced. We take the same approach here.

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A. The Void for Vagueness Doctrine

As noted above, “[a] statute can be impermissibly vague for either of two

independent reasons. First, if it fails to provide people of ordinary intelligence a

reasonable opportunity to understand what conduct it prohibits. Second, if it

authorizes or even encourages arbitrary and discriminatory enforcement.” Hill,

530 U.S. at 732. “The degree of vagueness that the Constitution tolerates . . .

depends in part on the nature of the enactment.” Betancourt v. Bloomberg, 448 F.3d

547, 552 (2d Cir. 2006) (quoting Flipside, 455 U.S. at 498). Here, because the

gravity knife law is a criminal statute that is not claimed to inhibit the exercise of

constitutional rights, “only a moderately stringent vagueness test [is] required.”

Id. at 553.

Whether a statute is unconstitutionally vague is an “objective” inquiry in

which we must determine “whether the law presents an ordinary person with

sufficient notice of or the opportunity to understand what conduct is prohibited

or proscribed, not whether a particular plaintiff actually received a warning that

alerted him or her to the danger of being held to account for the behavior in

question.” Dickerson, 604 F.3d at 745–46 (internal quotation marks and citation

omitted). “What renders a statute vague is not the possibility that it will

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sometimes be difficult to determine whether the incriminating fact it establishes

has been proved; but rather the indeterminacy of precisely what that fact is.”

United States v. Williams, 553 U.S. 285, 306 (2008). In other words, a statute is

fatally vague if it “proscribe[s] no comprehensible course of conduct at all.”

United States v. Powell, 423 U.S. 87, 92 (1975). “In reviewing a statute’s language

for vagueness, ‘we are relegated . . . to the words of the ordinance itself, to the

interpretations the court below has given to analogous statutes, and perhaps to

some degree, to the interpretation of the statute given by those charged with

enforcing it.’” VIP of Berlin, 593 F.3d at 186 (quoting Grayned v. City of Rockford,

408 U.S. 104, 110 (1972)).

B. Whether an Ordinary Person Had Notice that Plaintiffs’ Knives

Were Banned

Although arbitrary enforcement is “the more important aspect of

vagueness doctrine,” Kolender, 461 U.S. at 358, we understand plaintiffs to focus

on the notice element. Plaintiffs argue that the gravity knife law provides

constitutionally insufficient notice of which common folding knives are

proscribed for three reasons: (i) the defendants allegedly began to enforce the

gravity knife law in a novel and unprecedented way in 2010, (ii) the wrist‐flick

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test does not appear in the text of the gravity knife law, and (iii) members of the

public allegedly have no way to reliably determine which knives may lawfully

be possessed. Finding none of these contentions persuasive, we conclude that the

gravity knife law provided constitutionally sufficient notice that at least one of

the plaintiffs’ knives was unlawful to possess.

Plaintiffs first argue that notice is wanting because the defendants in 2010

unexpectedly began to apply the statute to common folding knives that could be

opened with the wrist‐flick test. This argument is meritless. The record shows

that the gravity knife law has been enforced against individuals who possess

folding knives for decades prior to 2010 and that the wrist‐flick test has been the

diagnostic tool for separating legal knives from illegal ones. Indeed, a booster of

the gravity knife law reportedly opened a knife with a flick of the wrist (rather

than the force of gravity) to demonstrate the dangers of gravity knives in 1957.5

More to the point, the district court found, based on unchallenged testimony

5 Emma Harrison, Group Seeks Ban on Gravity Knife, N.Y. TIMES, Dec. 19, 1957

(“Judge Cone selected a sleek, silverish object from weapons that the committee had on

display. He flicked his wrist sharply downward and the long blade shot forth and

anchored firmly in position. ‘You see,’ he said, ‘the blade leaps out with a flip of the

wrist and circumvents the law on switchblade knives.’”).

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from officers with decades of experience enforcing the gravity knife law against

folding knives, that defendants have consistently used the wrist‐flick test to

identify illegal folding knives since the ban was enacted.

Plaintiffs also contend that an ordinary person would not understand that

the statutory phrase “application of centrifugal force,” N.Y. Penal Law

§ 265.00(5), refers to the wrist‐flick test. But in evaluating a vagueness claim, we

consider not only the text of the statute, but also any judicial constructions, see

VIP of Berlin, 593 F.3d at 186, and the courts of New York State have long upheld

the application of the gravity knife law to common folding knives via the wristflick

test. State trial courts have accepted the wrist‐flick test as the measure of

banned gravity knives since at least the 1980s. See, e.g., People v. Hawkins, 781

N.Y.S.2d 627 (Table), 2003 WL 23100899, at *1 (N.Y. Crim. Ct. 2003) (upholding

complaint alleging that a knife “opened and locked when flipped”); People v.

Dolson, 538 N.Y.S.2d 393, 394 (N.Y. Co. Ct. 1989) (stating that a knife “appears to

meet the first part of the statutory definition of a gravity knife” because its

“blade can . . . be released from its sheath by a flick of the wrist”). And although

it appears that state appellate courts expressly approved of reliance on the wristflick

test to prove that a knife met the statutory definition only after some of the

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2010 enforcement actions had concluded,6 they had required proof of

“operability” for significantly longer. See, e.g., People v. Smith, 765 N.Y.S.2d 777

(1st Dep’t 2003) (finding evidence sufficient where “[a] detective twice

demonstrated the operability of the weapon in open court”); People v. Mashaw,

411 N.Y.S.2d 455, 456 (3d Dep’t 1978) (vacating conviction where operability not

established). Given the holdings of the state trial courts recited above, we think it

fair to infer that these convictions likewise turned on the results of the wrist‐flick

test. And in conjunction with the evidence that defendants have consistently

used the wrist‐flick test to identify illegal gravity knives since long before 2010,

this judicial authority is sufficient to have given an ordinary person notice that

folding knives that may be opened with a one‐handed flick of the wrist are

banned by the gravity knife law. See VIP of Berlin, 593 F.3d at 186–87.

Plaintiffs’ more substantial arguments concern the purported

indeterminacy of the wrist‐flick test. They argue that even if an ordinary person

6 See People v. Herbin, 927 N.Y.S.2d 54, 55–56 (1st Dep’t 2011) (finding the evidence

sufficient to sustain a gravity knife conviction where “officers release[d] the blade

simply by flicking the knife with their wrists”); Neal, 913 N.Y.S.2d at 194 (similar); cf.

Parrilla, 27 N.Y.3d at 402 (reciting that an officer “tested the knife to determine whether

it was a gravity knife by flicking his wrist with a downward motion”).

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had sufficient notice that the wrist‐flick test is the measure of illegality under the

gravity knife law, there is nonetheless no way to reliably identify legal folding

knives. This uncertainty, they claim, is a result of two features of the wrist‐flick

test. First, the test only confirms illegality. A positive result is strong evidence

that the knife is illegal, but, because a knife need not always positively respond

to the wrist‐flick test to be a gravity knife, see People v. Cabrera, 22 N.Y.S.3d 418,

420 (1st Dep’t 2016), a negative test is inconclusive. Second, the results of the

wrist‐flick test may vary depending on the tester’s skill, practice, and physical

traits. One person may be able to successfully flick open a knife that another

person cannot. And because guilt turns on whether a law enforcement officer can

flick open a knife, not whether the knife owner can, even an individual familiar

with the wrist‐flick test can never completely assure herself that a folding knife is

legal.

To the extent plaintiffs argue that the gravity knife law is unconstitutional

because the wrist‐flick test only measures illegality, the argument must be

rejected. Legislatures may functionally define crimes. See Powell, 423 U.S. at 88,

93–94 (rejecting vagueness challenge to statute prohibiting the mailing of

firearms “capable of being concealed on the person” (quoting 18 U.S.C. § 1715));

28

cf. Vrljicak v. Holder, 700 F.3d 1060, 1062 (7th Cir. 2012) (“[J]ust because it is

possible to replace a standard with a numeric rule, the Constitution does not

render the standard a forbidden choice.”). A legislature that does so need not

simultaneously create a safe harbor from prosecution, as plaintiffs seem to seek.

In Powell, for example, the Supreme Court sustained a proscription on the

mailing of concealable firearms without so much as suggesting that there must

be some second test to determine when a firearm cannot be concealed. See 423

U.S. at 88, 93–94. A functional definition, without more, does not offend the

Constitution.

Yet Powell does not entirely answer plaintiffs’ contention that the wristflick

test’s potential to yield variable results creates serious notice problems. In

Powell, the Supreme Court had an intermediate option to invalidating the statute

on constitutional grounds: imposing a limiting construction. Powell argued that

the statute was vague because it did not specify whether the term “person” in the

phrase “capable of being concealed on the person” referred to the person mailing

the gun, the person receiving it, or a hypothetical average person. See id. at 88

(quoting 18 U.S.C. § 1715). The Supreme Court construed “person” to mean to

mean “an average person garbed in a manner to aid, rather than hinder,

29

concealment of the weapons” and held that, so interpreted, the statute was not

unconstitutionally vague. Id. at 93.

Because the gravity knife law is a state statute, we must defer to the

interpretation given to it by the state courts. See Morales, 527 U.S. at 61; see also

Broder v. Cablevision Sys. Corp., 418 F.3d 187, 199–200 (2d Cir. 2005) (“[W]e are

generally obliged to follow the state law decisions of state intermediate appellate

courts.”). We are aware of no state court decision that has imposed a limiting

construction on the gravity knife law of the sort imposed in Powell. That is to say,

no state court has held that, for example, a knife is a gravity knife only if a person

of average skill or practice can open it.7 And the state courts have held that a

7 Plaintiffs argue that the New York Court of Appeals has held that the gravity

knife law reaches only those knives that “readily” respond to the wrist‐flick test. People

v. Dreyden, 15 N.Y.3d 100, 104 (2010) (stating that the gravity knife law “distinguishes

gravity knives from certain folding knives that cannot readily be opened by gravity or

centrifugal force”). We are not so sure. Dreyden held only that a criminal complaint

must include facts sufficient to give the defendant notice of the charges against him, see

id., and its description of the underlying statute more resembles dicta than statutory

construction. This reading is bolstered by a later decision upholding an accusatory

instrument containing the bare allegation that a gravity knife opened “with centrifugal

force.” People v. Sans, 26 N.Y.3d 13, 17 (2015). In any event, plaintiffs’ reading of Dreyden

would undercut their vagueness claim. After all, a rule that the gravity knife law only

reaches knives that readily respond to the wrist‐flick test would enhance the public’s

notice of which knives were proscribed and would do much to answer plaintiffs’

complaint that the wrist‐flick test is indeterminate.

30

knife can be a gravity knife even if it does not always respond positively to the

wrist‐flick test. See Cabrera, 22 N.Y.S.3d at 420 (“The fact that the officer needed to

make several attempts before the knife opened did not undermine a finding of

operability.”); Smith, 765 N.Y.S.2d 777 (similar). Given this statutory framework,

we think that there are circumstances in which an as‐applied challenge to a

gravity knife conviction might succeed. For example, a gravity knife conviction

might be constitutionally infirm if the knife could be flicked open to a locked

position only with great difficulty or by a person with highly unusual abilities. A

knife that responds inconsistently to the wrist‐flick test might also provide

grounds to challenge the law on an as‐applied basis. To take an extreme case, an

ordinary person would lack “sufficient notice . . . or the opportunity to

understand” that the gravity knife law bans a knife that can only be successfully

flicked open once in twenty attempts. Dickerson, 604 F.3d at 746.8

8 Plaintiffs also invoke the possibility of a knife loosening over time, as

apparently happened to Copeland’s knife. For the reasons discussed below, it is

unnecessary for us to decide whether Copeland had constitutionally sufficient notice

that his knife was unlawful to possess. Accordingly, we do not resolve whether a future

defendant to an enforcement action presenting similar facts may successfully contest

her prosecution on an as‐applied basis.

31

But we must evaluate plaintiffs’ notice argument as applied to the

plaintiffs’ facts and circumstances and not in the abstract. See VIP of Berlin, 593

F.3d at 189–90. We therefore consider whether the plaintiffs have shown “that

the statute in question provided insufficient notice that his or her behavior at

issue”—here, possession of the knives that formed the subject of the 2010

enforcement actions—“was prohibited.” Dickerson, 604 F.3d at 745. And because

a facial challenger must show that “no set of circumstances exists under which

the Act would be valid,” Salerno, 481 U.S. at 745, plaintiffs’ claim will fail if the

gravity knife law was constitutionally applied to even one of the knives that

formed the subject of the 2010 enforcement actions.

We conclude that Native Leather did not make this showing. As a seller of

knives, Native Leather was responsible for ensuring that its merchandise was

legal, and it possessed more resources and sophistication to make that judgment

than someone who uses a knife in her trade. See Flipside, 455 U.S. at 498

(observing that “businesses, which face economic demands to plan behavior

carefully, can be expected to consult the relevant legislation in advance of action”

and “may have the ability to clarify the meaning of regulation by its own

inquiry”). Yet prior to receiving the gravity knife subpoena in 2010, Walsh made

32

no meaningful effort to verify that Native Leather’s knives did not respond to the

wrist‐flick test. And in responding to the subpoena, Native Leather produced

more than 300 knives that Walsh simply guessed might be banned by the statute.

Native Leather’s lack of diligence significantly limits its ability to show

that the statute provided insufficient notice that it sold banned knives, because it

prevents it from offering evidence that the knives had responded differently to

the wrist‐flick test prior to the D.A.’s tests. Evidence that Native Leather had

scrupulously tested the seized knives and found that they did not respond to the

wrist‐flick test would certainly have been relevant to its notice argument. Native

Leather also made no showing that, for example, the government’s testers had

any unusual skill, or that the government retained any knives that responded but

poorly (if at all) to the wrist‐flick test. In sum, Native Leather offered no evidence

that any of its seized knives responded inconsistently to the wrist‐flick test, much

less that all of them did, as the demanding standard for facial challenges

requires. See id. at 494–95. Accordingly, Native Leather has not shown that it

lacked “sufficient notice . . . or the opportunity to understand” that it sold illegal

gravity knives. Dickerson, 604 F.3d at 745.

33

Native Leather makes much of the fact that the investigators arrived at the

one‐in‐ten failure rate on the day they began to test its inventory, but it points to

no evidence that any of the knives retained by the defendants in fact responded

to the wrist‐flick test at such a dismal rate. We therefore need not consider

whether applying the gravity knife law to such a knife raises any notice concerns.

Native Leather also protests that Walsh and employees of the independent

monitor occasionally had different results when testing its knives with the wristflick

test. However, the record as to any variation in the outcomes of the wristflick

test is sparse, and thus it is not apparent to us precisely how these knives

responded. In any event, although inconsistent results might give rise to notice

concerns, minor variation in the application of the wrist‐flick test only suggests

that the gravity knife law—like most laws—can give rise to close cases, and

“[t]he problem that poses is addressed, not by the doctrine of vagueness, but by

the requirement of proof beyond a reasonable doubt.” Williams, 553 U.S. at 306.

Plaintiffs also place great weight on the results of the in‐court knife

demonstration, which, they claim, shows that the wrist‐flick test produces

divergent results. However, we find no clear error in the district court’s decision

to credit a prosecutor’s testimony that one of the demonstrators used an

34

exaggerated technique that did not resemble the wrist‐flick test used by law

enforcement or prosecutors in New York City. More importantly, the

demonstration did not involve the knives that Native Leather produced for

testing in 2010, and therefore tells us nothing about whether Native Leather’s

own knives had some characteristics that rendered the application of the gravity

knife law unconstitutional.

Plaintiffs also rely on two trial court decisions that declined to apply the

gravity knife law to folding knives out of concern that the law would reach

seemingly innocent conduct. See United States v. Irizarry, 509 F. Supp. 2d 198, 210

(E.D.N.Y. 2007) (suppressing a “folding lock‐back utility kni[fe]” that responded

to the wrist‐flick test because the gravity knife law only covers “items . . .

manufactured as weapons”); People v. Trowells, No. 3015/2013, at *6 (N.Y. Sup. Ct.

July 11, 2014) (dismissing gravity knife complaint “in the furtherance of justice”

because of the perceived unfairness of enforcing the statute against people who

possessed seemingly legal tools). These decisions do not alter our conclusion.

Irizarry’s design‐based interpretation of the gravity knife law has not been

adopted by the state courts, see Herbin, 927 N.Y.S.2d at 55, and Trowells’

discretionary dismissal has no relevance to the issues before us. It remains the

35

case that it was well‐established in 2010 that the wrist‐flick test provided the

measure of guilt, and that there is no evidence that Native Leather’s knives

responded inconsistently to the wrist‐flick test.

We thus conclude that the gravity knife law provided constitutionally

sufficient notice that Native Leather’s knives were illegal. As a result, we need

not decide whether the gravity knife law provided adequate notice that the

individual plaintiffs’ knives were banned, and we express no view as to those

cases. See Flipside, 455 U.S. at 494–95.

C. Whether the Gravity Knife Law Provides Adequate Standards to

Law Enforcement

We next consider whether the gravity knife law satisfies “the requirement

that a legislature establish minimal guidelines to govern law enforcement.”

Kolender, 461 U.S. at 358.

Courts considering as‐applied vagueness challenges

may determine either (1) that a statute as a general matter

provides sufficiently clear standards to eliminate the risk

of arbitrary enforcement or (2) that, even in the absence

of such standards, the conduct at issue falls within the

core of the statute’s prohibition, so that the enforcement

before the court was not the result of the unfettered

latitude that law enforcement officers and factfinders

might have in other, hypothetical applications of the

statute.

36

Farrell, 449 F.3d at 494. Curiously, we understand the plaintiffs not to raise any

arbitrary enforcement arguments distinct from their core notice argument. In

other words, there is no discrete contention that the gravity knife law “authorizes

or even encourages arbitrary and discriminatory enforcement,” Hill, 530 U.S. at

732; plaintiffs’ basic argument is that the statute is void for vagueness because

the public cannot reliably identify legal folding knives with the wrist‐flick test. To

the extent this contention can be understood as a complaint about arbitrary

enforcement, it fails for the same reason their notice argument fails: Native

Leather did not show that the seized knives responded inconsistently to the

wrist‐flick test. Native Leather’s misconduct therefore fell “within the core of the

statute’s prohibition,” and we need not consider whether the statute provides

sufficient guidance as a general matter. Farrell, 449 F.3d at 494; accord VIP of

Berlin, 593 F.3d at 191–92 (“For the same reasons that it gave VIP adequate notice

regarding its March 2009 application, the language here . . . does not encourage

or authorize arbitrary enforcement.”).

Amici curiae separately attempt to show that the gravity knife law invited

arbitrary enforcement with evidence that the defendants have exempted certain

37

prominent retailers from aspects of the law. Citing five recent cases in which

defendants received substantial prison sentences for possession of a gravity

knife, they further contend that the defendants use the statute as a tool to harass

“those they deem undesirable.” Br. of Amici Curiae Legal Aid Society at 7.

Defendants, for their part, provide no meaningful account of why banned

gravity knives continue to be widely available in New York City retailers, and

respond to the discriminatory enforcement contention by pointing out that the

plaintiffs in this case have a “spotless pedigree.” D.A. Br. 46 n.35.

We are troubled by these signs that the defendants selectively enforce the

gravity knife law and are not entirely satisfied by the defendants’ responses. But

a pattern of discriminatory enforcement, without more, would not show that the

statute is unconstitutionally vague. What makes a statute unconstitutionally

vague is that the statute, as drafted by the legislature and interpreted by the

courts, invites arbitrary enforcement. See Kolender, 461 U.S. at 360–61. The test is

whether some element of the statute turns on the law enforcement officer’s

unguided and subjective judgment. Thus, the Supreme Court has invalidated

ordinances whose elements included acting in an “annoying” manner, Coates,

402 U.S. at 611, 614–16, and remaining in place without an “apparent purpose,”

38

Morales, 527 U.S. at 60–64. Such terms are so devoid of objective content that any

enforcement decision necessarily devolves upon an individual law enforcement

officer’s whim.

Whatever flaws infect the gravity knife law, a totally subjective element is

not among them. The gravity knife law has an objective “incriminating fact”:

either the knife flicks open to a locked position or it does not. See Williams, 553

U.S. at 306. In the ordinary case, a law enforcement officer is simply not called

upon to make a subjective judgment about whether the criterion of guilt is

present. The gravity knife law therefore does not “authorize[] or even

encourage[] arbitrary and discriminatory enforcement.” Hill, 530 U.S. at 732.

This is not to say that defendants’ enforcement priorities are immune from

scrutiny. It has long been the law that selective enforcement of a facially neutral

statute can violate the Equal Protection Clause of the Fourteenth Amendment.

See United States v. Armstrong, 517 U.S. 456, 464–65 (1996) (“A defendant may

demonstrate that the administration of a criminal law is ‘directed so exclusively

against a particular class of persons with a mind so unequal and oppressive’ that

the system of prosecution amounts to ‘a practical denial’ of equal protection of

the law.” (ellipsis omitted) (quoting Yick Wo v. Hopkins, 118 U.S. 356, 373 (1886))).

39

Evidence that the defendants target certain classes of people over others, or

certain types of retailers over others, would certainly be relevant to an equal

protection claim. However, because plaintiffs only advance a vagueness claim,

we express no view on whether the defendants’ enforcement priorities are

consistent with the Equal Protection Clause. We merely hold that they do not

prove that the statute was unlawfully enforced against the plaintiffs.

  

For the foregoing reasons, we conclude that at least one plaintiff did not

show that the gravity knife law was unconstitutionally vague as applied to it in a

prior proceeding. That alone requires us to reject plaintiffs’ facial challenge. See

Diaz, 547 F.3d at 101. Yet even if we were persuaded that the gravity knife law

was unconstitutionally applied to each of the three plaintiffs, the facial vagueness

claim would not succeed. As noted above, an ordinary facial challenge is, by

design, “the most difficult challenge to mount successfully, since the challenger

must establish that no set of circumstances exists under which the Act would be

valid.” Salerno, 481 U.S. at 745. Even setting aside plaintiffs’ own knives, we do

not think plaintiffs have met this burden. Plaintiffs acknowledge, for example,

that some common folding knives may have a “very light bias toward closure,”

40

with a blade that fits only “loose[ly]” in the handle, Reply Br. at 25, but they

make no effort to explain why an ordinary person would lack notice that such a

knife was proscribed by the gravity knife law. This is to say nothing of plaintiffs’

outright concession that the gravity knife law can lawfully be applied to “true

gravity knives.” Because plaintiffs have not satisfied the demanding Salerno

standard, their facial challenge to the gravity knife law fails.

IV. Whether the Gravity Knife Law Unconstitutionally Imposes Strict

Liability

Finally, amici curiae argue that the gravity knife law is unconstitutional

because it imposes strict liability on possession of an everyday item and because

possession of a gravity knife can, in some circumstances, be charged as a felony.

See Parrilla, 27 N.Y.3d at 404 & n.2. It is undisputed that the gravity knife law is a

strict liability statute in the relevant sense, as knowledge that a knife positively

responds to the wrist‐flick test is not required for a conviction. See id. at 402

(“[T]he mens rea prescribed by the legislature for criminal possession of a gravity

knife simply requires a defendant’s knowing possession of a knife, not

knowledge that the knife meets the statutory definition of a gravity knife.”).

Because many common folding knives can evidently be opened with a one41

handed flick of the wrist, many people may be unknowingly violating a statute

that can result in several years’ imprisonment. Amici’s argument that this violates

the Constitution can be understood in two ways. We conclude that neither is

persuasive.

Amici may be arguing that the lack of a mens rea merely exacerbates the

statute’s vagueness problems. To be sure, “[a] scienter requirement may mitigate

a law’s vagueness, especially where the defendant alleges inadequate notice,”

Rubin, 544 F.3d at 467 (citing Flipside, 455 U.S. at 499), and we have no doubt that

a scienter requirement would remedy many of plaintiffs’ complaints about the

gravity knife law. But the absence of a scienter element, without more, does not

make a law unconstitutionally vague; the inquiry remains whether the statute

gives adequate notice to the public and provides sufficient guidance to those

charged with enforcing it. See Hill, 530 U.S. at 732. For the reasons stated above,

we conclude that the gravity knife law was constitutionally applied to at least

one plaintiff in 2010 and that plaintiffs’ facial challenge accordingly fails.

Amici might also be understood to argue that, independent of the

vagueness claim, the statute’s lack of a mens rea itself violates the Due Process

Clause. Whether the Constitution sometimes requires criminal statutes to have a

42

mens rea is unsettled.9 Criminal intent is, of course, foundational to our system of

law. See Morissette v. United States, 342 U.S. 246, 250 (1952) (“The contention that

an injury can amount to a crime only when inflicted by intention is no provincial

or transient notion. It is as universal and persistent in mature systems of law as

belief in freedom of the human will and a consequent ability and duty of the

normal individual to choose between good and evil.”). Its importance at common

law informs a presumption in favor of inferring a mens rea requirement into a

statute that omits one. See Staples v. United States, 511 U.S. 600, 605–06 (1994).

But the Supreme Court has been at pains not to constitutionalize mens rea.

See, e.g., Smith v. California, 361 U.S. 147, 150 (1959) (“[I]t is doubtless competent

for the States to create strict criminal liabilities by defining criminal offenses

without any element of scienter . . . .”); United States v. Balint, 258 U.S. 250, 252

(1922) (“[I]n the prohibition or punishment of particular acts, the State may in the

maintenance of a public policy provide that he who shall do them shall do them

at his peril and will not be heard to plead in defense good faith or ignorance.”

9 And has been for some time. In 1962, one commentator summarized the

constitutional status of mens rea with the quip “[m]ens rea is an important requirement,

but it is not a constitutional requirement, except sometimes.” Herbert L. Packer, Mens

Rea and the Supreme Court, 1962 Sup. Ct. Rev. 107, 107 (1962).

43

(internal quotation marks omitted)). In particular, the Supreme Court has never

held that a strict liability possession statute violates the Due Process Clause. At

most, it has suggested in dicta that a legislature might be unable to create a strict

liability ban on indisputably harmless and everyday items. See United States v.

Int’l Minerals & Chem. Corp., 402 U.S. 558, 564 (1971) (stating that a strict liability

ban on “[p]encils, dental floss, [and] paper clips” “might raise substantial due

process questions”). Assuming arguendo that International Minerals accurately

locates the constitutional line, the gravity knife law falls comfortably on the safe

side of it. A knife is not a paper clip.

Amici’s argument to the contrary relies chiefly on cases interpreting federal

statutes. These decisions teach that a court should infer a mens rea requirement

into federal statutes that forbid possession of “apparently innocent,” even if

“potentially harmful,” devices, including ones as destructive as machine guns.

Staples, 511 U.S. at 610, 611. Amici seem to suggest that we should adopt the

statutory rule as the constitutional rule, if only because it is readily at hand. We

reject this invitation. The Supreme Court has long been careful to frame its mens

rea holdings as matters of statutory interpretation. Indeed, Staples itself notes that

Congress “remains free to amend [the statute] by explicitly eliminating a mens rea

44

requirement.” Id. at 615–16 n.11. As the Court has no more than sketched a

possible outer constitutional limit that lies well beyond the gravity knife law, see

Int’l Minerals, 402 U.S. at 564–65, we reject the due process argument.

CONCLUSION

Although we conclude that plaintiffs’ facial challenge to the gravity knife

law is unsuccessful, we note that legitimate questions have been raised about the

statute’s implementation. The statute’s reliance on a functional test and

imposition of strict liability on what can be a common, if dangerous, household

tool might in some instances “trap the innocent by not providing fair warning.”

Grayned, 408 U.S. at 108. And while the plaintiffs did not show that the statute

invites arbitrary enforcement as that term is used in the vagueness doctrine, see

Morales, 527 U.S. at 60–64, the sheer number of people who carry folding knives

that might or might not respond to the wrist‐flick test raises concern about

selective enforcement.

For these reasons, we believe that the legislative and executive branches

may wish to give further attention to the gravity knife law. Heeding the Supreme

Court’s admonition that facial challenges are disfavored because they “threaten

45

to short circuit the democratic process,” Wash. State Grange, 552 U.S. at 451, we

must stay our hand and defer to New York’s political branches.

The judgment of the district court is AFFIRMED.