Last year the U.S. House of Representatives passed the Protection of Lawful Commerce in Arms Act, a seemingly worthy proposal. Unfortunately, it really sought to give the gun industry almost blanket immunity from civil liability. The U.S. Senate rejected the bill, but is considering an amended version. While the amendments improve the legislation, Congress should investigate more.

The bill’s central purpose is to immunize the gun industry from liability for criminal use of its products. The gun industry is not responsible for gun buyers’ post-purchase conduct. But they do have a duty to take reasonable precautions to prevent criminals from buying firearms. The House proposal would severely reduce that duty, though, fortunately, the Senate’s largely restores it.

The Senate version closes a gaping loophole by requiring background checks for weapon sales at gun shows. The Senate amendments also allow lawsuits where a child is the victim, extend the assault weapons ban and direct the attorney general to regulate ammunition capable of piercing law enforcement officers’ body armor.

The Senate would still immunize gun manufacturers from liability even when they knowingly provide weapons to criminals. Gun manufacturers know their industry better than anyone else. If a manufacturer knows a distributor illegally sells weapons and still sells to that distributor, that manufacturer should be responsible to victims. Opponents of the bill contend this is a problem, while the gun industry claims it is not.

Gun manufacturers contend this bill is necessary to protect them from the costs of defending frivolous litigation. Frivolous litigation serves no one. But the courts can, and usually do, efficiently handle this problem by dismissing suits lacking merit and ordering offending plaintiffs and lawyers to pay court costs and even sanctions.

The gun industry gives as evidence of its claims that 33 cities and one state are currently suing them in connection with criminal shootings. Cities and state governments, however, seem poor candidates for the frivolous plaintiff label. Congress must be certain gun manufacturers’ complaints are correct. They should not grant blanket immunity to the gun makers unless courts are systematically mishandling frivolous lawsuits.