When a gunman opened fire inside a packed movie theater in July 2012, killing 12 and injuring 70, it did more than spread fear and heartbreak across the Denver suburbs. It helped revive the national debate over gun control.

The debate gained intensity in the state five months later when a gunman killed 20 children and 6 adults at a Connecticut elementary school, resulting in Democrats to require universal background checks and ban magazines that hold more than 15 rounds.

Gun control advocates boasted that they had found the formula to enact their policies in a libertarian swing state. Furious gun rights supporters recalled two state senators who supported the measures.

But, as the trial of theater shooter James Holmes is scheduled to begin Monday, the debate has quieted down.