Former Govs. Mitt Romney from Massachusetts and Sarah Palin from Alaska are fighting for the lead in national preferences for the 2012 Republican nomination after the exit of real estate mogul Donald Trump and ex-Arkansas Gov. Mike Huckabee, according to the latest Gallup poll. But the survey also shows a new candidate who could make a difference in the race: former Godfather's Pizza CEO Herman Cain.The poll found Romney with a narrow edge over Palin, but his 17 percent to 15 percent lead was within the survey's 4 percentage point margin of error.