A winter storm forced the Senate on Monday to approve a House-passed bill extending a ban on undetectable firearms instead of voting on a stronger version.
Current law requires guns to contain enough metal to be picked up by metal detectors, and that requirement would have expired Monday night without the Senate's action.
Many Democrats wanted to go further than a simple extension. Sen. Charles Schumer (D-N.Y.) said last week that the House bill doesn't go far enough, and he said he would try to pass an expanded version that takes into account possible loopholes created by the advent of 3D printing.
Schumer did try to pass the House bill with an amendment from him and other Democratic senators, but it was objected to by Sen. Charles Grassley (R-Iowa.). Grassley said his opposition was based on the last-minute nature of the change that Democrats were proposing.
"Today is the day that the current plastic gun ban expires," Grassley said. "The House had already passed a 10-year extension on a bipartisan vote, and the only way to be sure that the current ban remains on the books is to pass the House bill."
Schumer accepted that reality, and agreed in his own remarks that extending the law is a step in the right direction. But he said the Senate should work quickly to update the law to close possible loopholes created by 3D printers.
He and other Democrats say 3D printing allows guns to be manufactured in a way that lets people easily remove noncritical metal parts in order to avoid detection.
"So I would hope that we can pass a bill that not only extends the current ban, but would close the loophole hat allows for the manufacturing of guns that can evade detection by simply removing a piece of metal," he said.
Sen. Robert Menendez (D-N.J.) was more critical of Republicans for blocking what he said would be an improvement to the law.
"Today Senate Republicans turned a blind eye to the threat from ever-improving technology that can print out a plastic gun which avoids detection," he said. "Once again, hard-line gun safety opponents stood in the way of common-sense measures to keep our families safe — refusing even to close a loophole that would prevent 3D printed guns from evading metal detectors and x-ray machines."
Even without the storm, the Senate seemed likely to simply approve the House bill given that the current ban expires Monday night, and many Democrats in the House and Senate favored a simple extension of the law over changes that might allow it to expire. Before Thanksgiving, Schumer himself pushed for a simple extension of the law, before he decided that the House extension wasn't good enough.
Last week in the House, Democrats accepted the need to pass the simple extension but also said they would work to change the law later to require all critical gun parts to contain some metal.
"While I support the reauthorization of the Undetectable Firearms Act for 10 years, a 10-year extension should not be interpreted as an agreement that the statute should remain unchanged for that entire term," said Rep. Bobby Scott (D-Va.).
On the Senate floor Monday, Sen. Chris Murphy (D-Conn.) said it would be embarrassing if Congress couldn't at least extend the current ban. But he too said Congress needs to do work in the coming weeks to strengthen the ban to close the 3D printer loophole.
"This new technology that is pretty widely available already called 3D printing, has made it really easy to make firearms that comply with the existing law but are still potentially undetectable," he said.
— This story was updated at 6:12 p.m. to reflect the Senate vote.