Plastic guns combine the modern with the inexplicable. Using downloaded plans, the owner of a 3-D printer can make a handgun or assault rifle. The firearm is untraceable, invisible to metal detectors and requires no background check: a terrorist’s or criminal’s dream.

Barring a last-minute change, the how-to instructions will go online this week courtesy of a Texas distributor, who proudly calls his plan the end of “American gun control.” Congress has largely ignored the deadline and federal regulators gave up on a bid to stop the plan. Eight states are pressing for a legal Hail Mary, hoping for a court order to block online access. San Francisco Supervisor Catherine Stefani is asking city lawyers to draft legislation.

Critics of the weapons dub them “downloadable death” and “ghost guns,” both apt phrases. The firearms may lack the slick metal surfaces and heft of conventional weapons, but they’re just as lethal. Printing devices come with price tags that run from $5,000 to $600,000 with the quality of the plastic a major factor.

Homemade firearms aren’t new, but a basement gunmaker generally isn’t allowed to sell such weapons. With unmarked, self-made plastic weapons, that limitation won’t exist at all.

As usual, it’s hard to gauge the direction of the Trump administration. President Trump tweeted his concern, saying he’s conferred with the National Rifle Association: “I am looking into 3-D Plastic Guns being sold to the public. Already spoke to NRA, doesn’t seem to make much sense!” But he didn’t offer further details.

His words follow a decision to drop a five-year court fight to deny access to the downloadable instructions. The U.S. State Department had barred the blueprints, contending they violated export laws on weapons. But that legal strategy was dropped by the Trump team last month with no explanation. Come Wednesday, the plans are due to be fully available.

That outcome should be reversed. The president and Congress must find the will to limit guns, not ease the way for a whole new brand of weaponry that can’t be traced or kept out of the wrong hands.

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