Chafee is expected to change his party registration Thursday, The Providence Journal reported. Christine Hunsinger, his spokeswoman, said he will go to Warwick City Hall, where he formerly served as mayor.
Hunsinger said the reason for the change was "a recognition that the Democratic Party and he are aligned on policies and principles.'' She also said Chafee sees the need for "strength in numbers when it comes to fighting for Rhode Island taxpayers.''
The New York Times suggested Chafee might have more practical motives. He faces a tough fight for a second term next year after winning in 2010 with little more than one-third of the vote.
"His move comes from thinking, 'If I don't switch parties, I'm going to lose anyway,'" Wendy Schiller, a political scientist, told the Times. "And maybe as a Democrat, the president can come out for him wholeheartedly or at least help dry up the funding for the other candidates."
But Schiller, who teaches at Brown University, Chafee's alma mater, said President Obama might be reluctant to endorse Chafee in the Democratic primary. Two of the leading contenders in what could be a crowded Democratic field are Providence Mayor Angel Taveras, who is Hispanic, and a woman, State Treasurer Gina Raimondo.
Chafee is a member of a family that has long been part of Rhode Island's governing class. He served one term in the U.S. Senate, succeeding his father, the late John Chafee, who also served as governor, before losing to a Democrat in 2006.
A moderate Republican like his father, Chafee switched to independent after his 2006 loss.