Five justices said the "death penalty is invalid because it is imposed in an arbitrary and racially biased manner," while four other justices wrote that while they agreed with the majority's conclusions and invalidation of the death penalty, "additional state constitutional principles compel this result."
Washington Governor Jay Inslee, who imposed a moratorium on the death penalty in 2014, commented on the decision, calling it "a hugely important moment in our pursuit for equal and fair application of justice."
READ MORE: Catholic Church Announces Death Penalty Inadmissible
Washington has become the 20th state to ban capital punishment, which is currently used in 30 states of the country and is also used in the US for certain federal crimes. In three states, however, the death penalty is under moratoria. 23 people were executed and 39 sentenced to death across the US in 2017, which was the second-lowest annual total since 1972.