In one of the few legal setbacks dealt to the gun industry, the U.S. Supreme Court on Tuesday rejected the appeal of a gun manufacturer that is being sued by the families of children and adults senselessly slaughtered at Sandy Hook Elementary School in 2012 at Newton, Conn.

That lets stand the earlier ruling of the Connecticut Supreme Court, which said the lawsuit could move forward under a unique legal argument that could give gun safety advocates new tools in their effort to restore a measure of accountability to this industry.

The Sandy Hook families have been fighting since 2014 against protections afforded almost no other industry. In 2005, a Republican Congress gave in to pressure from powerful gun manufacturers and retailers, heavily aided by the National Rifle Association, and passed a law that protected gun makers and sellers from liability in civil claims brought by victims of gun violence or their survivors. Since passage of the Protection of Lawful Commerce in Arms Act, no one has successfully sued the gun industry.

But the law does contain a few exceptions, including for marketing practices that violate a state’s commerce laws. Key to the Sandy Hook families’ lawsuit is the argument that Remington Arms, manufacturer of the Bushmaster AR-15-style rifle used in the massacre, marketed a military-style assault weapon in a way that promoted its combat capabilities. Connecticut’s consumer protection laws prohibit advertising that promotes violent or criminal behavior.

In their lawsuit, the families argue that Remington “knowingly marketed and promoted the Bushmaster XM15-E2S for use in assaults against humans.” Among the evidence they cite: ads that promised the “mission-adaptable” shooter the “ultimate combat weapons system.” Another, the families said, promoted the “lone gunman” narrative with ads that said, “Forces of opposition bow down. You are single-handedly outnumbered.”

Such advertising goes well beyond touting a weapon’s legitimate hunting or self-defense capabilities. Unlike actual soldiers, civilians are not in need of “ultimate combat weapons systems” and are unlikely to run into “forces of opposition.” Such ads play into the sick fantasies that some shooters, sadly, carry out by committing mass murder against innocent victims.

Lawmakers in thrall to the gun industry have shown little appetite for even the most reasonable gun reforms and have given the industry legal protections so strong they have left victims with little recourse. Connecticut has a chance to change that, a little. Even if the court there finds for the families, the federal immunity law will remain largely intact. A victory, however, would give victims a badly needed avenue for accountability.

Forcing manufacturers and sellers to change the way they market such weapons won’t bring back the 20 young children and six adults who died that awful day in 2012. But it may temper the violent fantasy culture that some manufacturers have used to create a lifestyle out of the once-simple purchase of a gun for hunting, target shooting or self-defense.