"Republican candidate for Senate Thom Tillis makes a statement during a live televised debate with Sen. Kay Hagan, D-N.C., at UNC-TV studios in Research Triangle Park, N.C., Wednesday, Sept. 3, 2014. Third-party candidates rarely win Senate races, but they could play significant roles in several key races this year. The notion that Libertarian candidate Sean Haugh could cost Republican nominee Tillis the Senate seat in North Carolina, for instance, ""is a story line bein"