SEE AD AT SITE Newt Gingrich has a message for John McCain: Welcome to the 2012 race. On Wednesday, a super PAC backing Gingrich welcomed McCain’s endorsement of former Massachusetts governor Mitt Romney (R) by seizing on a Web ad, “Two Mitts,” that the Arizona Republican had run against Romney during the 2008 GOP nominating battle. The spot juxtaposes clips of Mitt Romney stating contrasting positions on issues including abortion rights and gun control throughout his political career. The salvo from the pro-Gingrich “Winning Our Future” super PAC comes as Gingrich is vowing to step up his campaign-trail attacks on...