California meanwhile, is in the middle of a debate over abolishing the practice in part because of its cost. The state, which is expected to hold a referendum on the issue next year, has spent $4 billion on its death row system and has executed 13 people since 1978.
In California, housing death row inmates is almost twice as expensive as housing someone in the general prison population, and trial costs can run up to $1 million per case, up to 20 times the cost of a murder trial where prosecutors are not asking for the death penalty, according to the Death Penalty Information Center.
A declining murder rate and growing numbers of life-without-parole sentences for the most violent criminals may be playing more of a role in the death penalty decreases than changes in public sentiment, prosecutors and victims' advocates say.
“I think that the numbers show that the majority of the public still believe that in those rare and outrageous cases that the death penalty is an appropriate sanction,” Scott Burns, the executive director of the National District Attorneys Association, tells MSNBC. “One of the reasons for that, I believe, is because … the criminal justice system has done a good job at targeting those violent offenders nationwide” and handing out “long and stiff sentences.”