NICHOLAS RICCARDI, Associated PressDENVER (AP) — 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. That argument gained intensity in the state five months later when a gunman killed 20 children and 6 adults at Newtown Elementary School in Connecticut. Democrats in the state legislature in 2013 muscled through new laws requiring universal background checks and banning 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.