Countdown to the primary: Four leading Republican U.S. Senate candidates share their visions

The tension between former U.S. Rep. Mark Walker and U.S. Rep. Ted. Budd -- and Budd's lack of visibility on the campaign trail in recent months -- has in turn helped former Gov. Pat McCrory maintain what political scientists and conservative polls view as a slim lead. Meanwhile, Army combat veteran Marjorie K. Eastman is seen as unlikely to win but could peel off enough votes from competitors to force a runoff contest in July.