Michele Bachmann, Ron Paul, Rick Perry and Mitt Romney all achieve roughly equal results against Barack Obama in a new Gallup poll of registered voters. When respondents were asked to choose between Obama and one of these four GOP presidential candidates, Romney fared the best, with 48 percent of registered voters saying they would vote for him against Obama. But the difference between his result and the result of Bachmann and Paul, the two candidates who placed first and second in the Ames Straw Poll, was within the poll’s margin of error.