Colorado became the 22nd state in the nation to abolish the death penalty when Gov. Jared Polis signed the legislature's repeal into law on Monday.
The death penalty is still on the books in every other state in the Mountain West except New Mexico. But University of Colorado-Boulder sociology professor Mike Radelet thinks that could change.
"The West has always been more respectful of individual rights," he said.
The West is following national trends that show more people favor life imprisonment over executions, Radelet said, and one factor is cost.
"Basically, lawyers cost more than prison guards," he said. "These things can go on and on and on, and I think the general public has gotten very sick of spending all this money to send people to the gurney."
Religious communities and the West's limited-government leanings also tend to conflict with capital punishment, Radelet said.
This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Boise State Public Radio in Idaho, KUER in Salt Lake City, KUNR in Nevada, the O'Connor Center for the Rocky Mountain West in Montana, and KRCC and KUNC in Colorado.