Connecticut's highest court on Thursday spared the lives of all 11 men who were on death row, saying it would be unconstitutional to execute them.
Connecticut's legislature voted in 2012 to abolish capital punishment for future crimes, but that law did not apply to inmates awaiting execution.
The court acted on an appeal from one of them, Eduardo Santiago, sentenced to die for a murder-for-hire killing in 2000.
"Connecticut’s capital punishment scheme no longer comports with our state’s contemporary standards of decency," the court said in a 4-3 decision. "It therefore offends the state constitutional prohibition against excessive and disproportionate punishment."
The ruling also found that executing prisoners has not discouraged would-be criminals from committing murder.
"In the absence of any indication that the death penalty, as administered in this state, has forestalled the commission of capital crimes, it is apparent that capital punishment no longer serves any meaningful deterrent function in Connecticut," the court said.
Governor Dannel Malloy, who signed the 2012 legislative enactment into law, said the ruling made for a "somber day."
"Our focus should not be on the 11 men sitting on death row, but with their victims and those surviving families members. My thoughts and prayers are with them during what must be a difficult day.”
Connecticut has carried out only one execution in the modern era of the death penalty. A serial killer, Michael Ross, was put to death by lethal injection in 2005 for murdering four women in the 1980s.
A total of 19 states and the District of Columbia have abolished the death penalty.