On Wednesday, the New York city council introduced a new bill that would make it illegal to use a 3D printer "to create any firearm, rifle, shotgun, or any piece or part thereof," without being a licensed gunsmith. And even the creator would be required to notify the New York Police Department and register the gun within 72 hours of completion.

The new municipal bill is the latest move to put pressure on Cody Wilson’s Defense Distributed group—which in recent months has advanced 3D- printed guns more than any other organization worldwide. In early May 2013, Wilson received a letter from the Department of State saying that distributing CAD files to make firearms was effectively illegal under International Traffic in Arms Regulations. The feds ordered him to remove the files, which he did. But The Pirate Bay and countless others have already made the files available via other online venues.

“I'm waiting for the shoe to drop—there's probably going to be an indictment of some kind,” Wilson told Ars by phone on Thursday. “They're going to come back.”

“So this evening [the White House] announces [the] arming of Syrian rebels,” Wilson added via text message minutes later. “[The Department of State] can literally put guns in the hands of terrorists, but fuck me [because] zomg 'national security.'"

The new local legislation marks the first time that a city in the United States has attempted to regulate 3D printed firearms.

Regulating guns or speech?

In recent weeks, New York state lawmakers introduced a bill that would “prohibit the manufacturing, sale, and use of firearms and ammunition magazines digitally made by individuals.” A California state senator has said he intends to introduce similar legislation in the Golden State.

In April 2013, a House of Representatives bill was introduced that would ban plastic guns or “any firearm that, after removal of grips, stocks, and magazines, is not as detectable as the Security Exemplar, by walk-through metal detectors calibrated and operated to detect the Security Exemplar.”

All of these legislative responses have come to the fore since Defense Distributed group successfully made AR-15 lower and related magazines and an entire handgun.

With all the proposed legislation, there are questions as to how such laws—whether it's local, state, or federal—would stand up to likely legal challenges.

“[There’s] no constitutional problem banning manufacture, sale, possession of all plastic gun[s], just as [there's] no problem banning machine guns, hand grenades, greater than .50 caliber long guns,” James B. Jacobs, a professor of constitutional law and a gun law expert at New York University, told Ars by e-mail.

“I'm sure [the New York state bill], or something like it, will pass. But the First Amendment will not permit banning posting software that would allow ‘printing’ such a weapon, just as we can't ban Al Qaeda literature on building pipe bombs.”