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    Wisconsin Lawyer
    July 16, 2021

    Knives Out: Regulating Blades in Wisconsin

    Wisconsin's regulation of knives has changed in recent years, especially regarding concealed carry, persons with prior felony convictions, and possessing knives in government buildings like courthouses.

    Peter R. Heyne

    swiss army knife

    “Is this a dagger which I see before me, the handle toward my hand?” – Macbeth, II.i.33-34

    Knives are almost everywhere. They are some of humanity’s earliest and most useful tools (for example, flint); and they have been to space (since Mercury 7, NASA has equipped astronauts with survival knives and machetes, and the new Orion suits for the Artemis Program to return to the Moon will feature rescue knives).

    Knives of myriad design and materials are today in the kitchen, the garage, the glove compartment, the tackle box, the keychain mini-multi-tool, the art studio, the shop, the office breakroom. Almost every adult, and many children, use knives and other bladed instruments with regularity. Many people carry and use knives, on their persons and in their vehicles, for a variety of uses. Knives serve general utility, both personally (for example, to cook; to work around the house and yard; to have in the car for emergencies; for self-defense), and also professionally, as a tool of their trade (such as farmers, butchers, plumbers, electricians, chefs, first responders, and police). Likewise, knives assist popular outdoor activities like hunting, fishing, hiking, and camping.

    But as the citation to the Scottish play above attests, in the wrong hands knives can also do great bodily harm. Not just daggers, but even a kitchen knife could maim and kill. When is a knife dangerous enough to warrant penalties, civil and criminal? What even qualifies as a “knife” (what about a box-cutter, straight razor, machete, or sharp pointed scissors)? Because knives are so ubiquitous, accurate definitions are essential to clear, consistent, and constitutional knife regulations.

    Because Wisconsin has no statutory definition for “knife” (for example, in Wis. Stat. section 939.22 Words and phrases defined), a standard lexical entry must suffice. Merriam-Webster defines knife as either 1) “a cutting instrument consisting of a sharp blade fastened to a handle” or 2) “a weapon or tool resembling a knife.”1 This broad definition for “knife” raises a key due process question for knife regulations: is the knife at issue a deadly weapon, or a tool?

    This article provides a three-part overview of Wisconsin knife laws, criminal and civil: a brief history of Wisconsin knife laws before passage of 2015 Wis. Act 149 [hereinafter Act 149]; a description of the major changes under Act 149, including the creation of Wis. Stat. section 941.231 (Carrying a concealed knife); and a summary of a municipal ordinance post-Act 149 banning knives from a county courthouse.

    History of Wisconsin Knife Laws

    Although state statutes on knives have changed substantially, in both criminal and civil cases Wisconsin courts have consistently treated knives as not all per se dangerous but instead have carefully examined the particular knife used to distinguish a deadly weapon from a tool.

    Peter R. HeynePeter R. Heyne, Marquette 2010, has been an assistant state public defender (SPD) in the Trial Division, Green Bay office since 2015. He presented on this topic at the SPD virtual conference in fall 2020. Get to know the author: Check out Q&A below.

    The author thanks Kelli Thompson, State Public Defender; Jennifer Bias, SPD Trial Division Director; and Katie York, SPD Appellate Division Director, for their support and feedback. The author also thanks Thomas Grieve, Marquette 2010, and Jon Paul Heyne, Ph.D., for their editorial assistance.

    Other states have regulated entire categories of knives since before the Civil War (for example, Tennessee outlawed Bowie knives in 18372 ), but Wisconsin does not appear to have had any categorical knife bans in the criminal code until after World War II. One reason could be Wisconsin’s rich history of outdoor life, enshrined in the broad protections of Wis. Const. art. I, sections 253 and 26.4

    But in the late 1950s, fears in the United States of juvenile delinquents wielding automatic knives, fueled by a reaction to films such as Rebel Without a Cause (1955) and 12 Angry Men (1957) and the Broadway musical West Side Story (also 1957), prompted federal5 and state bans on switchblades. In 1959, Wisconsin enacted Wis. Stat. section 941.24 (Possession of a switchblade knife).6 A 1987 Wisconsin Attorney General opinion interpreted the statute as also prohibiting butterfly knives,7 and in 1989 the Wisconsin Court of Appeals described a butterfly knife as an “illegal weapon.”8 But in 2015, the court of appeals held that under District of Columbia v. Heller9 and McDonald v. City of Chicago,10 Wis. Stat. section 941.24 violated the Second Amendment right of a person who possessed a switchblade in his own home for his protection.11

    Shortly thereafter (no apparent connection to this litigation), the Wisconsin Legislature enacted Act 149, which repealed Wis. Stat. section 941.24. Thus, at present, there are no criminal bans in Wisconsin on entire categories of knives (for example, switchblades or butterfly knives). Instead, the focus has shifted from the type of knife to the person possessing it. As discussed in the next section, individuals who cannot legally possess a firearm under Wis. Stat. section 941.29 (for example, because of a felony conviction) cannot now carry concealed knives that are dangerous weapons.

    Despite changing statutes, Wisconsin courts persist in requiring answers to two key questions of fact: 1) Was the knife designed as a deadly weapon (more like a dagger or combat knife)? 2) Regardless of the knife’s design, did its wielder have ill intent, use the knife as a deadly weapon, or both?

    Thus, for example, in the earliest appearance of a knife in Wisconsin case law, in 1838, still during the territorial period, a defendant was indicted for “an assault with a certain deadly weapon, commonly called a carving-knife.”12 The design details of this “commonly called … carving knife” (such as blade length, point, sharpness, hilt) are unclear; by its name, it appears to have been designed for the butcher’s shop or kitchen, not the battlefield. But whether society at the time deemed this carving knife to be a “deadly weapon” per se, in this case the defendant had ill intent and used the knife as a weapon, not a tool.

    Likewise, in 1859, after a defendant used a knife (of unspecified design) to repeatedly stab a victim, resulting in the victim’s death, the recently created Wisconsin Supreme Court approved the trial judge’s jury instructions that “to reduce the offense to manslaughter … the involuntary killing must be without a cruel or unusual weapon, and without any cruel or unusual means.”13 So “cruel” design and “cruel” use can transform a tool into a weapon.

    As such, in a torts suit a few years later, the supreme court ruled against a man, a farmer, who in a dispute over a wandering cow threatened a neighbor with a butcher knife.14 In an 1892 torts case, when analyzing the risk of a child’s Daisy BB-gun, the high court analogized, “A pocket-knife, that a boy must have to whittle and make things with, may become, in the hand of a bad boy, a most dangerous instrument of wrong and injury.”15

    In this vein, in 1997 the supreme court affirmed a student’s delinquency adjudication for carrying a concealed weapon. The juvenile had a nine-inch knife, locked in an open position, tucked in her waistband by her right hip under her shirt.16

    Likewise, in State v. Horton, the court of appeals rejected a sufficiency challenge to convictions for second-degree murder and endangering safety by conduct regardless of life, both while using a knife as a dangerous weapon.17 The defendant admitted stabbing two youths with a sharp-bladed steak knife (one of the victims died) but claimed that it was a fishing knife that he carried as a tool to vandalize video machines. The trial court instructed the jury that a dangerous weapon was “any device designed as a weapon and capable of producing death or bodily harm.”18

    The appellate court rejected the claim that the knife was merely a tool, because the knife had a long, very sharp blade, and with a hilt and a sheath, it followed the design of a dagger. Though the Horton court did not make the express connection, its analysis tracked Wis. Stat. section 939.22(10), which defines “dangerous weapon” generally for the criminal code. Relevant to knives are these two criteria: (1) “any device designed as a weapon and capable of producing death or great bodily harm” or (2) “any other device or instrumentality which, in the manner it is used or intended to be used, is calculated or likely to produce death or great bodily harm.”

    In sum, while statutes have changed, Wisconsin courts have consistently used the dual criteria of lethal design and lethal use or intent to distinguish knives that are deadly weapons from knives that are tools. Some knives, like daggers, are deadly by design; other knives transform into dangerous weapons because of the wielder’s intent and actions.

    Figure A: Edged Weapons Restricted in Specified County Buildings

    Sign on the entrance door to the Brown County Courthouse

    Sign on the entrance door to the Brown County Courthouse.

    Act 149 and Concealed Carry

    Passage of Act 149 was a sea change for both criminal and civil knife laws, in three ways. First, the legislature repealed Wis. Stat. section 941.24 (2013-14), thus ending the ban on switchblades and butterfly knives. The legislative history to this Act shows public support, including from law enforcement agencies, for decriminalizing spring-assisted knives, which have life-saving utility for police officers and other first responders.19

    Second, the Act amended the carrying a concealed weapon (CCW) statute, Wis. Stat. section 941.23, to exempt all knives entirely: “Notwithstanding s. 939.22(10), ‘dangerous weapon’ does not include a knife.”20 Now a person can legally carry concealed a switchblade, or butterfly knife, or a long, very sharp, hilted dagger like the one from Hortonabove, or a combat knife (for example, the U.S. Marine Corps Ka-Bar, or the Ontario Mark 3 (MKIII) used by Navy SEALS), or even a sword.

    Third, as the one exception to allowance of concealed-knife carry, the Act created Wis. Stat. section 941.231 (Carrying a concealed knife): “Any person who is prohibited from possessing a firearm under s. 941.29 [that is, any prior felony conviction (even nonviolent)] who goes armed with a concealed knife that is a dangerous weapon is guilty of a Class A misdemeanor.”

     But Wis. Stat. section 941.231 does not define “knife” or “dangerous weapon,” so it is unclear if anything with a blade, of any length, counts (for example, what about sharp garden tools or scissors?). The statute could have referenced Wis. Stat. section 939.22(10) cited above, with its dual criteria of lethal design and lethal intent or use. The legislature did just this in Wis. Stat. section 948.61(1)(a) Dangerous weapons other than firearms on school premises: “‘Dangerous weapon’ has the meaning specified in s. 939.22(10).”

    Wis. Stat. section 941.231 does not define “knife” or “dangerous weapon,” so it is unclear if anything with a blade, of any length, counts.

    Without such clear criteria, it is unclear if the law passes the two intertwined prongs of the due process void-for-vagueness test: 1) giving fair notice to the average person to know what not to do; and 2) having objective enforcement by law enforcement officers, prosecutors, judges, and juries.21 How do those with a felony conviction know exactly which knives they can carry? Likewise, with law enforcement officers and prosecutors deciding for themselves how bad a concealed knife is, how does one avoid differential arrest and charging decisions?22

    In this author’s practice in Brown County, law enforcement agencies have taken the absolutist position that the statute bans all concealed knives, no matter the lack of lethal design or lethal use or intent. With the phrase “that is a dangerous weapon” now rendered mere surplusage, even those with a nonviolent felony conviction cannot legally ever put in their pocket, or carry under their winter coat on a belt pouch, or keep in their glovebox for emergencies, a pocketknife or multi-tool available in every big-box-store camping aisle (knives that, by definition, conceal their blade in the handle when safely closed). No one with a felony conviction could ever go camping, hiking, bow hunting, or fishing and take a closed pocketknife or multi-tool, or sheathed skinning or filleting knife in their car, truck, tent, stand, tackle box, or boat. To avoid criminal prosecution, convicted felons would instead have to open carry naked blades, even when driving.

    In sum, Act 149 has substantially changed the laws on concealed carry of knives, but due process requires Wis. Stat. section 941.231 to define the key terms “knife” and “dangerous weapon.”

    Municipal Knife Regulations

    Act 149 also effected three changes in municipal knife laws. Created by 1995 Wis. Act 72, Wis. Stat. section 66.0409 originally applied only to firearms. Act 149 changed the statute’s title to “Local regulation of weapons” and established new regulations on knives regarding state preemption, possession in governmental buildings, and disorderly-conduct ordinance violations for open or concealed carry. As in the criminal code, though, there are due-process concerns regarding local knife bans.

    Establishing state preemption, Wis. Stat. section 66.0409(2) prohibits political subdivisions from enacting or enforcing an ordinance regarding any knife that is more strict than state statute.23 Interpreting this subsection, which it termed the “Local Regulation Statute,” the Wisconsin Supreme Court recently held that a political subdivision cannot ban knives and firearms on city buses, as long as the person complies with several statutes, such as the concealed carry law (and other laws that do not apply to knives anyway).24

    The only two exceptions to the Local Regulation Statute regarding knives allow a political subdivision to impose a sales or use tax(Wis. Stat. section  66.0409(3)(a)); and to prohibit possessing a knife in a local governmental building, such as a courthouse (Wis. Stat. section 66.0409(3)(c)). But like Wis. Stat. section 941.231, the Local Regulation Statute does not define “knife” or “dangerous weapon,” so a political subdivision could prohibit possessing any knife, even a utility knife, in any governmental buildings.

    Further, under Wis. Stat. section 66.0409(6), neither the state nor any political subdivision can prosecute a disorderly-conduct ordinance charge for either open carrying or concealed carrying a firearm or knife, unless there is proof of “a criminal or malicious intent.”25 This is a welcome departure from the standard two elements of disorderly conduct, Wis. Stat. section 947.01, which lack any intent requirement.26

    Like Wis. Stat. section 941.231, the Local Regulation Statute does not define “knife” or “dangerous weapon,” so a political subdivision could prohibit possessing any knife, even a utility knife, in any governmental buildings.

    As an illustration of a local regulation, see Brown County Code of Ordinances section 3.335 Edged Weapons Restricted in Specified County Buildings (Figure A).27 Given the cost for a violation (a maximum forfeiture, including court costs, is almost $80028 ), there are due-process issues.

    First, the ordinance lacks any intent element, like the open and concealed carry disorderly conduct statute discussed above. Nor is there an element of knowing possession29 of the prohibited edged weapon in a governmental building. And unlike the traditional trespass-to-land ordinance, there is no warning provision, whereby the person has an opportunity to leave the premises and store the knife somewhere else.30 A person coming to a courthouse from a work site, shop, or garage, for example, might forget a small utility knife in the person’s pocket when entering the courthouse. Such a knife does not look like the long-bladed, hilted Bowie-style knife on the courthouse door sign (see Figure A). Though the person in this situation would not have any criminal intent, with no defense of accident or mistake available, the person could then face a forfeiture much higher than the maximum forfeiture for texting while driving.31

    Furthermore, the ordinance’s definition of edged weapon (“an instrument for cutting, consisting essentially of a thin, sharp-edged metal blade typically fitted with a handle, such as a knife”) is at once too narrow and too broad. Not covered are deadly knives designed not for cutting but for stabbing, such as the “punch” or “push” dagger or knife, very compact and concealable in the palm of one’s hand (basically an arrowhead on a small T-grip handle). Some “tactical daggers” have no blade at all but resemble an ice pick or spike. Also, the ordinance bans only metal blades, but blades made of other materials (for example, ceramic, obsidian, or even carved bone or glass) also can be sharp.

    Conversely, the ordinance encompasses any instrument with a cutting blade, regardless of its design or length. Because the ordinance exempts only law enforcement officers and on-duty private-security and armored-car personnel, a person such as a county maintenance worker cannot carry a carpet cutter or multi-tool when working in the courthouse; nor could courthouse staff have scissors or letter openers at their desks. In sum, the ordinance does not distinguish tools from deadly weapons, raising similar due-process concerns as with Wis. Stat. section 941.231.32 To balance ensuring public safety with safeguarding individual constitutional rights, courthouse security should include fair notice and objective enforcement.


    Wisconsin knife laws, both criminal and civil, have changed dramatically since enactment of 2015 Wis. Act 149. But with the current definitional deficiencies in “knife” and “dangerous weapon,” there remain due-process issues, especially but not exclusively for individuals who have felony criminal convictions (even nonviolent ones). Not all knives are deadly daggers, and not all who carry them are malicious Macbeths.

    » Cite this article: 94 Wis. Law. 12-17 (July/Aug 2021).

    Meet Our Contributors

    How did you become interested in knife regulations?

    Peter R. HeyneResearching knife regulations and litigating criminal charges filed against people jailed for carrying pocketknives or utility knives comes from the heart. I still vividly remember receiving for my 14th birthday, during the summer before high school spent abroad with my cousins in Liechtenstein (a tiny principality in the Alps near Austria and Switzerland), the gift of a Victorinox Swiss Army knife (just like my dad had back at our farm in Texas). I spent many happy youthful hours using all the varied tools at home and in the wild (and still have a few scars on my hands to prove it).

    This past spring my father helped me find that knife, safe after all these years, and I cleaned, oiled, and sharpened it and gifted it to my own eldest on his 14th birthday. Maybe the Swiss craftsmanship will last for my son to give to his eldest child?

    I also have fond memories of my Gerber one-hand-opening Multi-Plier and machete, which I have used for everything from building an outdoor Greek hillside theater (and sets, props, and costumes) for summer Shakespeare plays; to erecting tree forts and castles in the backyard; to slicing up apples from our orchard and chopping wood for the firepit and fireplace. I hope that I have passed on to my children, and they can pass on to their own, the respect due to knives, probably humanity’s oldest tool.

    Peter R. Heyne, Assistant State Public Defender, Green Bay

    Become a contributor! Are you working on an interesting case? Have a practice tip to share? There are several ways to contribute to Wisconsin Lawyer. To discuss a topic idea, contact Managing Editor Karlé Lester at (800) 444-9404, ext. 6127, or email Check out our writing and submission guidelines.



    2 An Act to Suppress the Sale and Use of Bowie Knives and Arkansas Tooth Picks in this State, ch. 137, 22 Tenn. Gen. Assemb. Acts 200 (1838). For an in-depth nationwide historical analysis, see David B. Kopel et. al., Knives and the Second Amendment, 47 U. Mich. J.L. Reform 167 (2013).

    3 “The people have the right to keep and bear arms for security, defense, hunting, recreation or any other lawful purpose.”

    4 “The people have the right to fish, hunt, trap, and take game subject only to reasonable restrictions as prescribed by law.”

    5 15 U.S.C. § 1242 (1958) (Federal Switchblade Act (FSA), limiting the importability and interstate commerce of “switchblades”).

    6 “Whoever manufactures, sells or offers to sell, transports, purchases, possesses or goes armed with any knife having a blade which opens by pressing a button, spring or other device in the handle or by gravity or by a thrust or movement is guilty of a Class A misdemeanor.”

    7 Op. Wis. Atty. Gen 21-87 (unpublished).

    8 State v. Wallis, 149 Wis. 2d 534, 536, 439 N.W.2d 590, 591 (Ct. App. 1989).

    9 554 U.S. 570 (2008).

    10 561 U.S. 742 (2010).

    11 State v. Herrmann, 2015 WI App 97, 366 Wis. 2d 312, 873 N.W.2d 257.

    12 Rountree v. United States, Bur. 172, 1 Pin. 59, 1839 WL 816 (Wis. Terr. July 1839).

    13 Keenan v. State, 8 Wis. 132, 140 (1859) (seven intentional stab wounds).

    14 Barnes v. Martin, 15 Wis. 240, 245 (1862); see also Crichton v. Crichton, 73 Wis. 59, 40 N.W. 638 (1888) (drunken man brandished a butcher knife at his wife and threatened to kill her).

    15 Harris v. Cameron, 81 Wis. 239, 51 N.W. 437, 438 (1892).

    16 State v. Angelia D.B. (In Interest of Angelia D.B.), 211 Wis. 2d 140, 564 N.W.2d 682 (1997).

    17 151 Wis. 2d 250, 445 N.W.2d 46 (Ct. App. 1989).

    18 Id. at 255.


    20 Wis. Stat. § 941.23(1)(ap).

    21 State v. Muehlenberg, 118 Wis. 2d 502, 507, 347 N.W.2d 914 (Ct. App. 1984).

    22 See Grayned v. City of Rockford, 408 U.S. 104, 108 (1972) (“A vague law impermissibly delegates basic policy matters to policemen, judges, and juries for resolution on an ad hocand subjective basis, with the attendant dangers of arbitrary and discriminatory application.” ).

    23 “Except as provided in subs. (3) and (4), no political subdivision may enact or enforce an ordinance or adopt a resolution that regulates the sale, purchase, purchase delay, transfer, ownership, use, keeping, possession, bearing, transportation, licensing, permitting, registration, or taxation of any knife or any firearm or part of a firearm, including ammunition and reloader components, unless the ordinance or resolution is the same as or similar to, and no more stringent than, a state statute.”

    24 Wisconsin Carry Inc. v. City of Madison, 2017 WI 19, ¶ 69, 373 Wis. 2d 543, 892 N.W.2d 233. Laws inapplicable to knives include the “Vehicle Statute” Wis. Stat. § 167.31 (“Safe use and transportation of firearms and bows”) and Wis. Stat. § 167.30 (penalizing discharging a missile from a firearm or bow, etc., near a park).

    25 See, e.g., Village of Somerset v. Hoffman, No. 2015AP140, 2016 WL 2859565 (Wis. Ct. App. May 17, 2016) (unpublished opinion citable for persuasive value per Wis. Stat. § 809.23(3)(b)) (reversing civil forfeiture judgment involving person who was loitering around school and children, while openly carrying a rifle, but there was no evidence of any criminal or malicious intent).

    26 Wis JI-Criminal 1900.

    27 Full text available online at

    28 The penalty for violating Brown County Code of Ordinances section 31.13 (Trespass to Land) is a forfeiture of not more than $500. Per the Wisconsin Circuit Court Fee, Forfeiture, Fine and Surcharge Tables,, the maximum forfeiture of $500, plus costs, is $767.50.

    29 Wis. Stat. § 941.23 (Carrying a concealed weapon) has a knowledge element. See Wis JI-Criminal 1335, element 2: “The defendant was aware of the presence of the weapon.”

    30 Brown County Code of Ordinances § 31.13 (Trespass to Land) “Whoever enters or remains on any land of another after having been notified by the owner or occupant not to enter or remain on the premises ….”.  Full text available online at

    31 See Wis. Stat. §§ 346.89(3) (Inattentive Driving), 346.95(2) (penalty): forfeiture not less than $20 nor more than $400.

    32 See City of Milwaukee v. Nelson, 149 Wis. 2d 434, 446, 439 N.W.2d 562 (1989) (“A statute or ordinance is unconstitutionally vague if it fails to afford proper notice of the conduct it seeks to proscribe or if it encourages arbitrary and erratic arrests and convictions.”).

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