Both sides are preparing for the fight by strengthening their lobbying forces in Colorado.
Mayors Against Illegal Guns, a group launched by New York City Mayor Michael Bloomberg, has set up shop in the state, hiring two new lobbyists to get their message out at Colorado's state house. And gun industries are hiring lobbyists to protect themselves from restrictive gun bills that could hurt business.
In Colorado guns are not just for sport, they are for safety. Pro-gun groups worry new restrictions will hurt individuals abilities to protect themselves.
"Like many Western states, large numbers of people live long distances from law enforcement. Response times are longer. In some areas, 25 minutes would be a quick response time," Brown says. "What would have stopped the Aurora theater shooting was a person with a gun and a concealed carry permit."
Brown admits "this is shaping up to be a big battle," but says that his Republican allies won't flinch on guns.
Like in the U.S. House of Representatives, Colorado's Republicans are more conservative then they were a decade ago and they are more ready to fight against new gun laws.
"The swing districts are represented by Democrats," says Laura Chapin, a Democratic strategist who is working in the state to pass stronger gun laws. "What you have left are very hardcore conservatives from very conservative districts."