Chafee switched from Republican to Independent in 2007 but he's always been a Democrat. He is an Obama supporter (endorsed him in 2008 and 2012) and spoke at last year's Democratic National Convention.
Independent Rhode Island Gov. Lincoln Chafee is joining the Democratic Party ahead of his bid for a second term.
The former Republican U.S. senator left the GOP in 2007 and was elected as the nation's only independent governor in 2010.
Two Democratic sources say Chafee plans to change his party registration to join the party.
Chafee has been saying for months that he was thinking about the switch, noting that he shares many positions with Democrats and that joining the party will help with fundraising.
The move further complicates next year's Democratic primary and sets up the possibility of a three-way matchup with Providence Mayor Angel Taveras and Treasurer Gina Raimondo