Three Republicans are bunched within five points of each when potential GOP presidential candidates are matched up for 2012 with former Massachusetts Gov. Mitt Romney barely on top, according to a Fox News/Opinion Dynamics poll conducted July 21-22. The margin of error for the part of the survey dealing only with Republican voters is 6 points. Romney leads with 22 percent, followed by former Arkansas Gov. Mike Huckabee with 21 percent and former Alaska Gov. Sarah Palin with 17 percent. Former New York City mayor (we're dealing with a lot of "formers" here) Rudi Giuliani polls 13 percent, former House...