Reed Saxon / AP A bullet casing showing identification codes, at center, is shown through a microscope at a news conference at the Los Angeles Police Academy

It sounds like something from a futuristic thriller: police pick up spent bullet shells, find a tiny code on them that reveals what gun they were shot from and then use the ID to track down the killer. The technology to do this, called microstamping, is actually available today, but what’s stopping it from being used — and many criminals from being caught — is politics.

There are battles raging across the U.S. over microstamping, with supporters of the new technology squaring off against the gun lobby, which is strongly opposed. It is hard to see why the critics are so upset — and why they put so little value on microstamping’s potential to help fight crime.

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Gun violence in the U.S. is an epidemic. American gun-ownership rates are the highest in the world, with a remarkable 88 guns per 100 people. America also ranks No. 1 out of the top 26 high- and middle-income countries in gun mortality. In an average year, almost 100,000 people in the U.S. are shot or killed with a gun.

When police investigate gun crimes, they are often stymied by a lack of evidence. Guns are involved in the vast majority of murders, and according to the FBI, nearly 40% of all killings go unsolved because of lack of evidence. In many shootings, bullet casings are the only tangible evidence police have.

This is where microstamping comes in. If it were required, every gun would need to have a microscopic code stamped on the tip of its firing pin. When a bullet leaves the gun, its shell casing would be stamped with the code, which could be retrieved from the casings found at crime scenes. The code could lead the police to the person who fired the gun — or at least to its original purchaser.

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When the gun lobby fights gun-control legislation, its logic is clear: it does not like laws that prevent people from owning or using guns. But microstamping does neither. These codes just make people who fire guns accountable for where their bullets end up. Gun owners who use their guns lawfully shouldn’t be concerned.

Critics of microstamping have put forth an array of weak objections. They argue it’s too expensive. But the cost has been estimated at between 50¢ and $6 a gun — hardly a budget breaker. They also argue that the technology is not reliable. But a new study funded by the Department of Justice has found that when two shell casings are recovered, the code can be read 90% to 99% of the time.

The opposition to microstamping is the sort of knee-jerk reaction that gun-rights activists generally have to any law that affects gun use in any way — no matter how reasonable or beneficial. It’s the same reasoning that has led the gun lobby to oppose banning assault weapons and so-called cop-killer bullets.

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Despite the weakness of their case, the opponents of microstamping have been winning so far. Only one state — California — has enacted a law that requires microstamping, and since it was signed in 2007, it has been blocked by fights over patents. New York’s legislature is considering a microstamping bill as well, but it isn’t clear if it will gain any traction. One political blog reported that the National Rifle Association (NRA) had been “flooding Albany with cash” — a major obstacle to getting the bill through. Bills in at least four other states have also stalled.

The gun lobby has been on a roll. In recent years, the Supreme Court has interpreted the Second Amendment in a pro-gun way and used it to strike down municipal gun-control laws. Members of Congress are so afraid of the NRA that strong federal gun control has been a dead letter for years. Having done so well on the issues that really affect hunters and other lawful gun owners, the gun lobby should lighten up on the ones that do not — like microstamping — and show the nation that gun owners care not only about their own rights but also about the rights of innocent victims of gun violence.

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