The Bureau of Alcohol, Tobacco, Firearms and Explosives has struggled without a permanent director since 2015. So when President Biden tapped 25-year ATF veteran David Chipman to lead the agency, one would have imagined that the Senate would prioritize confirming a nominee with such eminent qualifications. Instead, Mr. Chipman’s nomination has languished in Senate confirmation purgatory, facing unified Republican opposition and noncommittal attitudes from several key Democrats.

The problem is the same one that has foiled ATF confirmations since the director’s job became Senate-confirmable in 2015: the gun lobby. After leaving the ATF, Mr. Chipman worked as a policy adviser for the gun violence group that former representative Gabrielle Giffords (D-Ariz.) founded after a crazed gunman shot her in the head. Gun zealots’ substantive opposition to Mr. Chipman has crystallized around his support for a ban on assault weapons — a policy that 6 in 10 Americans also favor. Mr. Chipman’s opponents also accuse him of lacking the expertise to lead the agency, a particularly absurd complaint about a lifelong civil servant who earned his stripes working terrorism cases in New York and Oklahoma City.

The real problem is that Mr. Chipman, himself a gun owner, has said things mildly critical of U.S. gun culture’s excesses. He has warned that people sometimes buy guns to give themselves a sense of protection or control, but that having a gun in the house without proper training or storage is risky, urging new gun owners to “hide it behind the cans of tuna and beef jerky that you’ve stored in the cabinet.” Explaining the popularity of the AR-15 rifle, Mr. Chipman said in 2018, “I would compare it to the same reason Americans might want a muscle car or enjoy a muscle car: It’s American-made, it has outsized power.” Statements such as these have riled sportsmen’s groups that see them as dismissive of gun enthusiasts.

This opposition says more about gun advocates’ toxic obsession with firearms, and the pervasive denial of reality that goes with it, than Mr. Chipman’s suitability for a job that should be filled by someone in touch with the facts. In truth, introducing guns into homes without proper precautions leads to large numbers of preventable firearm deaths every year. In fact, AR-15s are unnecessary for hunting, protection or any other legitimate civilian application, and their popularity reflects poorly on supposedly responsible gun owners.

The ATF should be conducting more research and releasing more information on how guns get to criminals. The agency should run more and tougher investigations on irresponsible gun sellers. Mr. Chipman has emphasized the need to combat firearms trafficking, which should be a top priority as urban crime rates rise. Gun zealots have targeted the ATF for years. Their cockamamie conspiracy theories and bizarre infatuation with the weapons of war should not continue to hobble this agency’s lifesaving mission.

Senators should generally defer to the picks that presidents make to staff their administrations, except in exceptional circumstances. The only thing exceptional about Mr. Chipman is his obvious suitability for the job.