Mike Huckabee has a 45-44 advantage over Obama, aided largely by a 44-38 lead with independents. There continues to be no evidence of any negative fallout for Huckabee after murders of police officers committed by an ex-Arkansas inmate whose sentence he had commuted. His 35/29 favorability breakdown is actually slightly better than it was in November before that incident.
Mitt Romney does the next best, trailing Obama 44-42. His favorability is 36/32, and he's the most popular Republican among independents (41/32). Romney actually matches Huckabee with GOP voters this month and gets over 50%, ending a trend in his numbers that had seemed to spell difficulty for snagging a Republican nomination.
Sarah Palin trails Obama 49-41 largely because she loses 14% of the Republican vote to him, making her the only one of the GOP candidates we tested who Obama could get double digit crossover support against. At the same time Palin continues to be the most well liked potential GOP candidate within her party- at 71% favorability. Her problem appears to be that the Republicans who don't care for her will go so far as to vote for Obama instead of her.
Source: Public Policy Polling
PDF of Poll: Download