SPRINGFIELD, Ill. | Illinois abolished the death penalty Wednesday, more than a decade after the state imposed a moratorium on executions out of concern that innocent people could be put to death by a justice system that had wrongly condemned 13 men.
Gov. Pat Quinn, a Democrat, also commuted the sentences of all 15 inmates remaining on death row. They will now serve life in prison with no hope of parole.
State lawmakers voted in January to abandon capital punishment, and Mr. Quinn spent two months reflecting on the issue, speaking with prosecutors, crime victims’ families, death penalty opponents and religious leaders. He called it the “most difficult decision” he has made as governor.
“We have found over and over again: Mistakes have been made. Innocent people have been freed. It’s not possible to create a perfect, mistake-free death penalty system,” Mr. Quinn said after signing the legislation.
Illinois will join 15 other states that have done away with executions.
The executive director of a national group that studies capital punishment said Illinois’ move sets it apart from other states that have eliminated the death penalty because many of those places rarely used it.
“Illinois stands out because it was a state that used it, reconsidered it and now rejected it,” said Richard Dieter, of the Death Penalty Information Center, in Washington.
Prosecutors and some victims’ families had urged Mr. Quinn to veto the measure.
The governor offered words of consolation to those who had lost loved ones to violence, saying that the “family of Illinois” was with them. He said he understands victims will never be healed.
Illinois’ moratorium goes back to 2000, when then-Gov. George Ryan, a Republican, made international headlines by suspending executions. Mr. Ryan acted after years of growing doubts about the state’s capital-punishment system, which was famously called into question in the 1990s, after courts concluded that 13 men had been wrongly condemned.
Shortly before leaving office in 2003, Mr. Ryan also cleared death row, commuting the sentences of 167 inmates to life in prison.
Illinois’ last execution was in 1999.
Mr. Quinn promised to commute the sentence of anyone else who might be condemned before the law takes effect on July 1.
New York and New Jersey did so in 2007. New Mexico followed in 2009, although new Republican Gov. Susana Martinez wants to reinstate the death penalty.
Anti-death penalty activists said other states have looked to Illinois as a leader on the issue ever since the moratorium began.