Former Massachusetts Gov. Mitt Romney has chosen his horse in the South Carolina Republican gubernatorial primary, becoming the fourth potential presidential candidate to make a bet on the winner. Romney's picked Nikki Haley, the state representative from the conservative Lexington suburb of Columbia.

It's a heck of a choice: Haley has unparalleled credentials as a fiscal conservative and has fought for transparency within the legislature. She's not from Washington. She's battled forces of status quo within the Republican Party.  She's also an Indian-American pro-life woman, so you can guess what the national press will focus on.  Romney's Mormon religion is viewed with suspicion by a healthy chunk of the Republican primary electorate in South Carolina, so there's little downside potential....but huge upside potential, if Haley wins, becomes popular, and decides to endorse Romney back.

This is a crowded primary of a primary; Mike Huckabee is backing the Lt. Gov. Andre Bauer; the McCain-Graham establishment is behind Attorney General Henry McMaster; Good ol' Fred Thompson is throwing his weight behind Rep. Gresham Barrett.

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