The Illinois Senate voted to abolish capital punishment, sending the historic issue to Governor Pat Quinn and putting the state back at the centre of an ongoing national debate.
In a state that has removed 20 wrongly condemned people from death row since 1987, the Senate voted 32-25 to end state-sponsored execution more than a decade after a former governor halted the punishment he said was "haunted by the demon of error".
"We have a historic opportunity today, an opportunity to part company with countries that are the worst civil rights violators and join the civilised world by ending this practice of putting to death innocent people," said Senator Kwame Raoul, the Chicago Democrat who sponsored the measure.
National experts and advocates said repeal in Illinois - which has executed a dozen people in the last three decades and at one time had 170 condemned inmates - puts weight behind the national discussion.
"This is a state in which this was used and then stopped, it was debated for years, fixed - or reformed - and finally there was a resolution by just getting rid of it, so that's about as thorough a process as any state could do," said Richard Dieter, executive director of the Death Penalty Information Centre. "That's significant."
But Democrat Mr Quinn, already wrapped up in a debate over a massive tax increase that could impact his political future, will not say what he will do with the legislation.
He supports the death penalty but said he would not lift the moratorium on executions imposed in 2000 by then-Governor George Ryan until he was sure the system worked.
Former law enforcement officials in the Senate argued prosecutors need the threat of death to get guilty pleas from suspects who opt for life in prison.
They said allowing police and state's attorneys to continue seeking death will make them more willing to accept reforms in the ways crimes are investigated and prosecuted.
Others argued citizens still want the option of the death penalty for the worst of crimes.
"It's not a question of vengeance," said Senator Bill Haine. "It's a question of the people being outraged at such terrible crimes, such bloodletting."
Illinois would join 15 states and the District of Columbia in ridding its books of capital punishment, including three - New Jersey, New Mexico, and New York - since 2007.