Those who continue to believe that Romney can be stopped are focused — as is the campaign of Newt Gingrich — on the possibility of a long delegate fight. They have largely given up hope of anyone winning a knockout victory over Romney, hoping instead that some other candidate can prevent the former Massachusetts governor from wrapping the race up before the Republican National Convention, which is set for Tampa, Fla., in late August. “We have never gone through a delegate fight like this,” said Bob Vander Plaats, an influential conservative and the head of the Iowa-based Family Leader organization....