The Washington Senate has approved a measure that officially abolishes the death penalty, just months after the state's Supreme Court unanimously struck down capital punishment as arbitrary and racially biased.

The measure passed by the Senate Friday would make that court ruling permanent by removing capital punishment as a sentencing option for aggravated murder and mandating instead a sentence of life in prison without possibility of parole. The bill passed on a 28-19 vote and it now heads to the House for consideration. Gov. Jay Inslee has said he will sign the measure if it makes it to his desk.

Execution was already extremely rare in Washington, and a governor-imposed moratorium has blocked its use since 2014. But the court's October opinion eliminated it entirely, converting the sentences for the state's eight death row inmates to life in prison without release.

The court did not rule out the possibility that the Legislature could come up with another manner of imposing death sentences that would be constitutional, which led Attorney General Bob Ferguson to request legislation to change state law.

Democratic Senator Reuven Carlyle of Seattle, the bill's sponsor, said that the governor and court had already taken a position on the death penalty and that it was time for the Legislature to do the same.

"It is time to close the chapter on this particular policy in a way that is respectful of the judicial process that has embarked for so many years and it's also respectful of the civil dialogue that the American people have embraced," he said.

With last year's court ruling, the death penalty has been overturned or abolished in 20 states and the District of Columbia, and several states are considering measures this year. An additional three states — Oregon, Colorado and Pennsylvania — currently have moratoriums.

The concerns cited in those states have ranged from procedural matters, such as the information provided to sentencing jurors in New York, to worries about executing an innocent person or racial and other disparities in who is sentenced to death, as was the case in Washington. A statistical analysis by University of Washington sociologists showed that although prosecutors were not more likely to seek the execution of black defendants, juries were about four times more likely to sentence black defendants to death.

Senators opposed to the measure argued that the death penalty should be retained for the most heinous cases, and as a tool for prosecutors to use to gain information about other victims.

"As a society, if we value innocent human life, we need to preserve the ultimate message to those who have taken it or might take it," said Republican Sen. Steve O'Ban of University Place.

There have been 78 inmates, all men, put to death in Washington state since 1904. The most recent execution in the state came in 2010, when Cal Coburn Brown died by lethal injection for the 1991 murder of a Seattle-area woman.