Attorneys general from 19 states are fighting in federal court to stop a Texas company from posting digital blueprints for 3D-printed plastic guns on the Internet. Should Alabama’s attorney general join them?

Yes, says Joseph Siegelman, who’s running for attorney general in November as a Democrat. Law enforcement doesn’t want guns it can’t trace on the streets, he said, and he supports that.

Incumbent Republican Attorney General Steve Marshall, however, says a court fight isn’t necessary. “The United States Attorney General has made it clear that undetectable plastic firearms are already illegal under current federal law,” Marshall said Wednesday.

When AL.com readers recently voted on which election issues are important to them, 3-D guns ranked last among 18 issues. The poll garnered more than 9,500 total votes.

The difference between Marshall and Siegelman centers on the fact the 3D gun issue has two parts: tracing them and detecting them. A “printed” plastic gun would have no serial number to make its history available to police – which is what Siegelman is talking about – but it might have metal parts such as a trigger to make it detectable at an airport.

The Untraceable Firearms Act of 1988 makes it a federal crime to make a gun that can’t be detected by the walk-through metal detectors at American airports. The NRA didn’t oppose the law because it didn’t affect any guns on the market at the time, and the NRA isn’t particularly concerned about Internet blueprints today.

“Many anti-gun politicians and members of the media have wrongly claimed that 3-D printing technology will allow for the production and widespread proliferation of undetectable plastic firearms,” NRA Vice President Chris Cox said recently. “Regardless of what a person may be able to publish on the Internet, undetectable plastic guns have been illegal for 30 years. Federal law passed in 1988, crafted with the NRA’s support, makes it unlawful to manufacture, import, sell, ship, deliver, possess, transfer, or receive an undetectable firearm.”

The current round in the fight over 3D guns started earlier this year when the Trump administration stopped the Justice Department’s fight to block a Texas company from posting 3D gun blueprints online.

The attorneys general picked up the fight saying that once the gun blueprints become widely available online, they will become “a bell that cannot be un-rung.”

The guns are made now by a process called additive manufacturing, also called 3D printing. It’s a process known as Fused Deposition Modeling (FDM), where a digital file or image is sliced into layers. The printer uses a type of plastic familiar in the home – think smartphone cases or Legos – that becomes soft and shapeable when heated. The machine deposits the plastic in layers according to the original design.

Guns “printed” from metal would be much stronger and safer, but machines capable of doing that kind of work can cost upwards of $100,000. NASA is using them now to print rocket parts, and the agency would like to print entire engines in the future. It’s the idea that the price and skills needed to make 3D printed metal objects, including guns, will drop while their reliability goes up that causes the most concern.

“Traceability. If you print it in your garage there’s no traceability,” University of Alabama in Huntsville engineering professor Dr. Judy Schneider said. “That’s exactly where the issue would be.”

“With printing the plastics, I don’t think anyone believes you’re going to have a fireable weapon,” Schneider said. “It would probably blow up and take you out, and Darwin wins. With the metal, right now we’re still having issues with the quality of what we’re producing. There would still be a lot of concern about having something that’s structurally sound…. I can see printing up firing mechanism, but I have a hard time imagining being able to make the barrels.”

Schneider’s comment illuminates yet another corner of today’s complicated firearms market. There is a market today in parts such as barrels, stocks, shoulder pieces for rifles, even the popular AR-15 combat rifles. Some believe the argument over 3D printed guns is a sideshow so long as this market is large and free-wheeling. And that’s not even considering the millions of existing guns floating around America today.

But Schneider’s students have already built a 3D printer capable of making metal parts in the basement of their building at UAH. “It’s feasible,” she said. “It wasn’t that expensive to do. We’re using solid wire feedstock rather than a powder, but people are building these in their garages.”

Law enforcement officers around the country are concerned about the spread of unlicensed, untraceable guns. And that concern is what drives Siegelman’s position.

“Whenever an issue like this comes up, the first thing I am going to do is reach out to law enforcement and get their thoughts,” Siegelman said. “These weapons are undetectable, they’re untraceable and we don’t need to give criminals an additional opportunity to get a weapon that our law enforcement has no way of knowing about.”

This story is one in a series of in-depth reports exploring key issues on Alabama voters' minds as they approach the Nov. 6 general election. The topics were determined using polling from the Public Affairs Research Council of Alabama and informal polls of AL.com readers. For more coverage of issues facing the next governor, go to al.com/election.