This past December, which marked the fifth anniversary of the Sandy Hook Massacre, also brought another grim milestone. The year saw the most mass killings in the United States since USA Today began tracking them in 2006. Mentally unstable assailants in Las Vegas, Nevada and Sutherland, Texas—wielding assault weapons such as the one used in Newtown—tipped last year’s total number of dead in these incidents to 208.

Hedge fund Cerberus purchased Bushmaster Firearms International in 2006 to begin building a firearms conglomerate. Bushmaster manufactured the AR-15 that Adam Lanza used to kill 26 people at Sandy Hook Elementary School. The weapon’s design is the basis for the M16, the standard rifle of the U.S. military. Its major attribute is its ability to fire rapidly, with devastating force, requiring little skill or training. Using the weapon, Lanza fired more than 150 rounds, killing 20 first-graders, six adults and himself, in just five minutes.

In marketing the AR-15, Bushmaster emphasizes that it is a military-grade “combat” weapon like those used by Army Rangers, Navy Seals, and other elite forces. AR-15s are also prominently featured in first-person shooter games popular with many young men, including Lanza. Bushmaster’s own documents attribute the strength in AR-15 sales to its popularity with a “younger demographic.” Bearing out its youth appeal, Adam Lanza requested and received his AR-15 as an 18th birthday present from his mother, Nancy Lanza, who he killed before going to the elementary school.

There is no conceivable hunting or self-defense need for a weapon that can discharge a 30-bullet magazine in a matter of seconds. Any other product so perfectly designed for deadly illegal results would be vulnerable to lawsuits. In fact, in 2004 Bushmaster contributed to a $2.5 million settlement after it was discovered the D.C. Beltway sniper had used an AR-15 in his attacks. But in 2005, Congress enacted to immunize gun makers from tort claims. The 2005 Protection of Lawful Commerce in Arms Act prevents almost all civil suits against those who make or sell guns.

So this uniquely dangerous product is also uniquely protected from liability for the harms inflicted by the product. The result is Bushmaster may manufacture and market the AR-15 as a mass-killing machine, with almost no fear of damage suits in the wake of mass murders.

The families of many of those killed at Sandy Hook are now suing Bushmaster for “negligent entrustment,” which is one of the few exceptions to gun-maker immunity. The Connecticut Superior Court dismissed the suit before even hearing evidence, and the case is now on appeal to the Connecticut Supreme Court. The outcome of the appeal is yet to be heard, but courts have dismissed similar suits. Negligent entrustment is a matter exclusive to state law, and torts professors from Stanford, UConn, Yale, and other schools have opined that the suit should go forward.

But even if this one suit can proceed, the PLCAA should not. We can protect the right to sell and own guns for lawful purposes without protecting the marketing of combat assault weapons to the public. Gun makers, like all other manufacturers, must be subject to the state law safeguards that usually protect the American people. If they are not held accountable, more tragedies like Sandy Hook are sure to follow.