Colorado Gov. John Hickenlooper (D) signed a package of new gun control measures into law in 2013, including universal background checks and the ammunition magazine limit. Support for the new gun laws resulted in the first-ever recall election in state history, which ousted two Democrats -- Senate President John Morse (Colo. Springs) and state Sen. Angela Giron (Pueblo).

A third recall effort against another Democrat, state Sen. Evie Hudak (Westminster), over her support of the gun control legislation, resulted in her resignation in November.