It is not well known or recognized, but it is reality that more than half of the Democratic Presidential contenders for 2016 were actually NOT always identified as Democrats.
We have Bernie Sanders of Vermont, the most successful Independent and Socialist in Congress in American history! He has allied with the Democrats in caucuses for years, but only finally declared himself a Democrat when he announced his candidacy for President.
We have Lincoln Chafee, who is the son of a former Republican Senator, John Chafee, who was also a Richard Nixon cabinet member as Secretary of the Navy in the 1970s; succeeded his father in the Senate as a Republican; then became an Independent when he ran for Governor of Rhode Island; and only in 2013 switched his loyalties to the Democratic Party.
We have newly announced former Senator Jim Webb of Virginia, who switched from Republican to Democrat before running for the Senate in 2006, but was a Ronald Reagan cabinet member as Secretary of the Navy in the 1980s, just as John Chafee was more than a decade earlier.
And then we have Hillary Clinton, who as a high school student was a supporter of Republican Barry Goldwater for President in 1964, although she never registered as a Republican!
Only Martin O’Malley of Maryland and likely future candidate Joe Biden have an “unblemished” record as Democrats throughout their lives!