The GOP faces a wide playing field in 2012, as 21 Democrats and two independents who caucus with Democrats are up for re-election. With only 10 Republican held seats up, that gives Republicans ample opportunity to win the seats necessary to gain a majority.
But there are early signs that the same intra-party feuds that limited huge pickups in the Senate in 2010 are re-emerging for 2012. Members who would be likely locks for re-election - Indiana Sen. Richard Lugar (R) and Maine Sen. Olympia Snowe (R) -- could well face serious primary challenges from Tea Party candidates. And Democratic members who look vulnerable - like Montana's Jon Tester - could benefit from ideologically divided Republican fields.