Here’s a superficial article explaining a recent Washington State Supreme Court decision:
Seattle PI, 12/31/15: High court: No constitutional right to carry a knife in Seattle
Upholding a city of Seattle ban, the Washington state Supreme Court has ruled that there is no constitutional right to carry a knife.
Writing for the majority, Justice Charles Wiggins said neither the state constitution nor the Second Amendment of the U.S. Constitution block the city law against carrying knives. The 5-4 split decision enables local restrictions against knives that likely could not be extended to firearms.
“While almost any common object may be used as a weapon, that does not necessarily mean that possession of otherwise innocuous objects that could be wielded with malice will trigger the constitutional protections afforded to ‘arms,’” Wiggins said in the majority opinion. …
The article is accurate as far as it goes. Wayne Evans was pulled over for speeding in Seattle, admitted to the officer that he had a sheathed paring knife, and was arrested. Seattle bans the carry of all fixed-blade knives, plus all knives with a blade longer than 3½ inches. Evans appealed his conviction on 2nd Amendment grounds, and lost, because paring knives are not “arms”.
But this omits several important points. For the details, you need to read the actual Supreme Court decision:
Evans lost this appeal because he was unable to prove (to the satisfaction of a majority of the justices) that his paring knife was an “arm” in the 2nd Amendment sense. The majority opinion states:
…We hold that the right to bear arms protects instruments that are designed as weapons traditionally or commonly used by law abiding citizens for the lawful purpose of self-defense. …
The four dissenting justices said, basically, that’s a stupid argument, because obviously all sorts of knives have been traditionally or commonly used for self-defense, so they’re all protected by the 2nd Amendment. Unfortunately, they didn’t persuade a fifth justice to agree with them.
So, basically, Evans lost because his knife was too little.
The majority opinion makes this clear in a footnote:
…many knives banned under the Seattle ordinance may be arms deserving constitutional protection. … In a different case under appropriate facts, the ordinance’s “broad prohibition” on carrying arms for purposes of self-defense may well be constitutionally infirm. … We reserve judgment on this issue for an appropriate case.
Evans’ appeal had another flaw: he failed to argue that the Seattle ordinance was unconstitutionally broad or vague. The majority notes this in another footnote:
…Amicus curiae Washington Association of Criminal Defense Lawyers newly raises the contention that the ordinance is unconstitutionally vague and thus violates the due process clause of the Fourteenth Amendment and Washington Constitution, article I, section 3. But Evans never argued that the ordinance was vague, too broad, or improperly sweeps within its prohibitions innocuous objects like tools. This court “will not address arguments raised only by amicus.”…
So, although the knife ordinance remains on the books for now, the majority has provided a roadmap for challenging its constitutionality on two grounds.