The legal strategy underpinning a $73 million settlement against the company that manufactured the military-style rifle used to kill 26 people at Sandy Hook Elementary School on Dec. 14, 2012, could expand the scope of the Connecticut Unfair Trade Practices Act—and have ripple effects in courts across the country.

For the first time, attorneys for the plaintiffs used CUTPA to satisfy the predicate exception to the Protection of Lawful Commerce in Arms Act, a federal law enacted in 2005 that provides gunmakers with immunity from civil liability for crimes committed by third parties with their products.