The two laws, passed in 2013 by Colorado’s Democratic-controlled legislature with scant Republican support, banned ammunition magazines that hold more than 15 rounds and required background checks for all private gun sales and transfers.
The bills were introduced in response to a shooting spree in 2012 that killed 12 people at a suburban Denver movie theater, and the slaying later that same year of 20 children and six adults at an elementary School in Newtown, Connecticut.
But they immediately met resistance from critics, including most of Colorado’s elected sheriffs, who said they severely restricted citizens’ constitutional right to own and bear arms.