The governor's moratorium affects 737 people—more than a quarter of the country's death row inmates.
America's courts still don't have clear protections for defendants with severe mental illness.
After hearing the last appeal from a man on death row, the Washington State Supreme Court ruled on Thursday that the death penalty, as applied in the state, is unconstitutional.
Seventeen inmates in Oklahoma are awaiting set execution dates.
The case once more raises the issue of persistent racial bias in North Carolina's history of sentencing black defendants.