Mitt Romney was a winner in Wisconsin\'s Republican presidential primary Tuesday, giving him a sweep for the day, the major networks projected. NBC, CBS, ABC and Fox all projected the former Massachusetts governor was the winner in Wisconsin, Maryland and the District of Columbia. CNN said Romney now has won more than half of the 1,144 delegates he needs to wrap up the GOP nomination that would put him in a head-to-head battle with Democratic President Barack Obama in November. With 19 percent of Wisconsin\'s precincts tallied, CNN said Romney had 42 percent of the vote to 39 percent for former U.S. Sen. Rick Santorum of Pennsylvania, 11 percent for U.S. Rep. Ron Paul of Texas and 6 percent for former U.S. House Speaker Newt Gingrich of Georgia. Despite failing to win, Santorum, the former U.S. senator from Pennsylvania, said he would forge on, saying the primary season was only at its \"halftime,\" MSNBC reported.