Obama campaign says GOP field remains uncertain

By KEN THOMAS | December 13, 2011 | 9:46 AM EST

WASHINGTON (AP) — President Barack Obama's top campaign advisers say they are uncertain about which Republican challenger will emerge next year but are predicting a long GOP primary contest that they say will produce a weaker opponent in 2012.

Democrats have targeted former Massachusetts Gov. Mitt Romney as the most likely Republican challenger to Obama. But they now say former House Speaker Newt Gingrich's rise in the polls has made the GOP contest very unpredictable.

Obama campaign strategist David Axelrod says Republican candidates are "being tugged to the right every day" and are "mortgaging themselves" for the general election by shifting rightward on many issues.

Campaign officials say their organizational efforts will help them next year. They say they have more staffers on the ground in Iowa than the Republicans.