Chafee is expected to formally announce his candidacy at an event planned at 10 a.m. Wednesday in Washington, his campaign treasurer, Caswell Cooke Jr., told the Providence Journal.
Chafee was a Republican in 1999 when he was nominated to fill his late father's seat in the Senate, according to CNN. He went on to win election to the seat in 2000 but lost in 2006 to Democrat Sheldon Whitehouse.
Four years later, in January 2010, Chafee successfully ran as an Independent candidate for governor of Rhode Island. While in office, he switched to join the Democratic party, The Associated Press reported. At the end of his term, he declined to run for reelection and left office in 2014.
He vied for the 2016 Democratic presidential nomination but failed to gain traction in the crowded field. In 2019, he moved to Wyoming and joined the Libertarian Party, according to the AP.