By Ali Elkin

Lincoln Chafee on Thursday became the second Republican-turned-Democrat to offer himself as an alternative to all-but declared presidential candidate Hillary Clinton.

"Campaigns are the time for debates about the vision for our future and for voters to asses the character and experience of those offering ideas," the former Rhode Island governor said in a Web video.

It's the second flirtation with White House ambitions for Chafee. In 2004, he considered challenging then-President George W. Bush in the New Hampshire primary over Iraq policy, but ultimately backed down.

Chafee's announcement that he's "considering a run for president" as a Democrat, completes a three-part political odyssey. Like his father, longtime Sen. John Chafee, he represented Rhode Island in the Senate as a Republican, but lost the job in 2006 to Sheldon Whitehouse.

In 2011, Chafee won the governorship of Rhode Island as an independent. He switched party affiliation again, to Democrat, before ultimately abandoning plans to seek a second term in the face of low approval ratings.

While Clinton has yet to make her widely anticipated candidacy official, Chafee is the second Democrat to form a presidential exploratory committee. The other is former Sen. Jim Webb, a one-time member of President Ronald Reagan's administration. He became a Democrat to run for Senate in 2006.

In his inaugural campaign video, Chafee embraces President Barack Obama, saying he has "led admirably" and blaming Republicans for leaving the economy "in shambles" prior to Obama's 2008 election.

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