A new poll shows Mitt Romney, who is locked in a prolonged GOP nomination fight, with lagging approval ratings, raising questions about his strength in a likely November match-up with President Obama. Half of those surveyed hold unfavorable views of the GOP front-runner, a new Washington Post/ABC News poll released Wednesday finds. In the poll, 50 percent of all surveyed and 52 percent of registered voters held unfavorable opinions of Romney. Thirty-four percent hold positive views on Romney, the lowest for any leading presidential contender in Post/ABC polls dating back to 1984. The poll also finds that Romney’s unfavorability tops...