The 72-year-old's announcement clears the way for younger members of the party to run. Attorney General Bob Ferguson, who gained a national profile by challenging the travel ban and other policies of former President Donald Trump, and state Public Lands Commissioner Hilary Franz have expressed interest.
He made a bid for the Democratic presidential nomination in 2020 on an environmental platform, but struggled to gain traction in a crowded Democratic field and had trouble meeting the requirements needed to appear on two high-profile stages: the third Democratic National Committee debate in Houston and a CNN town hall focused on climate change.
He also vowed to protect gay rights and abortion access as conservative states constrained them, and he bought the state a three-year stockpile of a popular abortion drug in anticipation of court rulings that could limit its availability. His liberal politics made him a boogeyman to critics on the right, who argued that he infringed on individual liberties. Soon after Washington suffered the first known COVID-19 outbreak in the nation, he issued emergency orders mandating mask wearing and requiring that state employees and health workers be vaccinated.