Three U.S. cities have filed a lawsuit against the Defense Department over the failure to properly report military convictions to the national database used to for background check, a failure that played a prominent role in the mass shooting a church in Texas earlier this year:

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 Federal Bureau of Investigation and its 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 F.B.I. the names of service members convicted of crimes that disqualify 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 American history — officials from New York, 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 one in three court-martial convictions that should have barred defendants from gun purchases had gone unreported by the military.

Having a federal court oversee compliance, the cities in the lawsuit say, would reduce the chance that a tragedy like the massacre in Sutherland Springs, Tex., happens again.

If the lawsuit is successful and the military fails to adhere to a court order to demonstrate compliance with the law, a federal judge could hold the defendants in contempt, lawyers for the plaintiffs say. The lawsuit names as defendants the Defense Department and its secretary, James N. Mattis; the Departments of the Air Force, Army and Navy and their respective secretaries; the directors of the military’s criminal investigative organizations; and the commander of the Navy’s personnel command.

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.

“I believe the active involvement of the court system will produce the desired results,” said Ken Taber, the lead lawyer for the plaintiffs. “This will impose an outside monitor to make sure that what should have been done for two decades is finally done.”

Another lawyer for the plaintiffs, Adam Skaggs, added that the lawsuit was not seeking a new interpretation of law — merely that a judge be enlisted to help ensure the military’s adherence to existing rules.

“After 20 years of failure, outside monitoring by the courts is clearly necessary to guarantee that the reporting failures that led to the Texas church shooting never happen again,” said Mr. Skaggs, the chief counsel of the Giffords Law Center to Prevent Gun Violence.

“The department continues to work with the services as they review and refine their policies and procedures to ensure qualifying criminal history information is submitted to the F.B.I.,” said Tom Crosson, a Pentagon spokesman. He declined to comment specifically on the lawsuits\

The lawsuit, of course, is rooted in the shooting at a church in a small town in Texas that resulted in the death of twenty-six people back in November. Several days after the shooting, it was reported that the shooter, David Kelly, had previously served in the Air Force. During that time, he was convicted on domestic violence charges after he severely beat his ex-wife and broke the skull of his infant stepson. Additionally, Kelley had served approximately one year in a military prison for the offense before being released from the military. These charges were never properly reported to the national criminal background check system used to verify that people convicted of violent crimes are not allowed to purchase weapons, and we later learned that this was not an isolated incident. Several weeks after the shooting in Texas, it was reported that the Air Force and perhaps other branches of the military had failed to report similar offenses to the national system on an ongoing basis for a number of years. The result of this, of course, is that potentially thousands of violent offenders who should have been denied the ability to purchase a weapon were able to do so because the background check did not show any convictions on their record for violent crimes. It’s unclear at this point just how extensive the failure to report actually reaches, and whether it reaches beyond the Air Force, but at the very least it seems clear that there has been a systemic breakdown in the background check system due to clear failures on the part of the Defense Department to do what the law requires.

It’s worth noting that this lawsuit is separate from claims that the families of the victims of the Texas shooting are making against the Federal Government over the failure to properly report Kelley’s military conviction. Those claims will have to proceed through the normal process one has to follow to make claims against the Federal Government and could take several years to resolve. In this lawsuit, the three cities are seeking some form of court-ordered compliance with things that the law already requires, namely that the relevant Federal agencies and service branches properly report crimes as required by the law. Given the admission by the Federal Government that there have been systemic failures by at least one branch of the military, it seems likely that the cities will prevail and that the Defense Department will have to agree to submit to some form of court monitoring to ensure that it is properly complying with the law. Of course, this won’t be of much help with regard to the potentially thousands of people who have been allowed to purchase weapons they should not have been legally entitled to own.

Here’s a copy of the Complaint:

New York Et Al v. Defense Department Et Al by Doug Mataconis on Scribd