The Obama White House is fearful of a Democratic primary challenge as Obama contemplates running for reelection in 2012, according to New York Times White House Correspondent Helene Cooper.Appearing on the Chris Matthews Show ths weekend, Cooper said Obama's advisers are concerned they'll face an intraparty challenge from the left as did President Jimmy Carter when Sen. Ted Kennedy took him on in 1980. A wounded Carter was soundly defeated later that Fall by Republican Ronald Reagan.One person who could lead a credible challenge from the left would be Sen. Russ Feingold of Wisconsin. However he is set to go...