I'm not sure I would go as far as saying it's been more conservative but it has been a pendulum state. We were among the first states, if not THE first, to legalize abortion in the 1960s. Dick Lamm I think was the sponsor. 

The Republicans of the late 19th Century here were split down the middle when the nation dropped silver coinage and fed the Panic of 1893, which for us was almost as bad as the Great Depression. YOu ended up with the Silver Republicans and the most prominent Republican in the state, Sen. Henry Teller, joined the rump party and finally switched parties to finish up as a Democrat. But we also had hard right politicos like Sen. Rice Means, said to have been in the Klan (but in Denver in the 1920s, who wasn't?), Sen. Lawrence Phipps and others.