Three major cities have filed a lawsuit against the Defense Department for its failure to report many criminal convictions in the military justice system to the FBI and to the national gun background-check database.

The Pentagon has for years run afoul of federal laws intended to keep guns out of the hands of felons and domestic abusers by not transmitting to the FBI the names of service members convicted of crimes that disqualify them for gun ownership.

This is what allowed Devin P. Kelley, who was convicted of domestic assault in the Air Force, to buy at a store the rifle he used to kill 25 people, including a pregnant woman whose fetus also died, at a Texas church in November.

Now, after two decades of serious lapses — and one of the worst mass shootings in U.S. history — officials from New York City, Philadelphia and San Francisco are trying to force a change. Their suit would require the Pentagon to submit to federal court monitoring of its compliance with the reporting laws it has broken time and again.

“This failure on behalf of the Department of Defense has led to the loss of innocent lives by putting guns in the hands of criminals and those who wish to cause immeasurable harm,” Mayor Bill de Blasio of New York said.

The cities say they are suing because their police departments regularly access the federal background-check database and rely on it to provide accurate information about who should be prevented from buying guns.

The Pentagon has repeatedly been chided since the 1990s by its own inspector general for woefully failing to comply with the law. In a 2015 report — and another one issued just a few weeks ago — investigators said that nearly 1 in 3 court-martial convictions that should have barred defendants from gun purchases had gone unreported by the military.

Generally, the military is required to report felony-equivalent court-martial convictions for crimes that are punishable by more than one year in prison, and any convictions for domestic violence. As with those of similar convictions in civilian courts, the records are supposed to block defendants from buying guns.

The military must also report anyone who receives a dishonorable discharge, which precludes gun ownership. Federal law also bans ownership by drug abusers, people subject to certain restraining orders, and mentally ill people.

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