Lincoln Chafee will be jumping in on the Democratic side in a few hours. He served as a Republican U.S. Senator from 1999-2007, was elected Governor of Rhode Island as an independent in 2010, became a Democrat in 2013, and left office this past January. While a Senator, he was the only Republican to vote against the Iraq War, which is what his candidacy seems to be centered around, based on his rhetoric so far (since Clinton voted for it).