MICHAEL BARONE: Harry S. Obama? “Pundits have lately been comparing Barack Obama to Jimmy Carter, suggesting he is a likely loser in 2012. But my American Enterprise Institute colleague Norman Ornstein, writing in the New Republic, compares Obama to Harry Truman, suggesting he might outperform the polls and win. . . . Truman won many votes from Democrats still upset about the Civil War. Few such votes are available to Obama or congressional Democrats in 2012. In addition, Truman’s victory was due to two ‘F factors’ — the farm vote and foreign policy — the first of which scarcely exists today and the second of which seems unlikely to benefit Obama in the same way.”