The gun manufacturer that made the AR-15-style rifle used to kill 20 young children and six adults at Sandy Hook Elementary School in 2012 can be held liable for their deaths, Connecticut’s Supreme Court ruled Thursday.

The 4-3 decision, which reversed a lower court’s ruling, gives the green light for a lawsuit brought on behalf of the parents and relatives of the Newtown victims to proceed. The lower court held that gunmakers were shielded by a 2005 law that protected them from liability when their products were used to commit crimes.

Plaintiffs say that Remington, the gun company, manufactured a weapon that’s too dangerous for civilian use, and then glorified it through aggressive marketing, which made it attractive to the 20-year-old Sandy Hook shooter, Adam Lanza.

“The families’ goal has always been to shed light on Remington’s calculated and profit-driven strategy to expand the AR-15 market and court high-risk users, all at the expense of Americans’ safety,” attorney Joshua Koskoff said in a statement on Thursday. “Today’s decision is a critical step toward achieving that goal.”

The case has the potential to bring seismic shifts to the world of gun rights and gun control, as it could set a precedent whereby gun manufacturers will be held liable in the aftermath of mass shootings. In the past, lawsuits brought by victims’ family members against gunmakers have been dismissed by courts that cited the 2005 Protection of Lawful Commerce in Arms Act.