Mississippi's GOP nominee for the Senate will be decided in a June 24 runoff between Sen. Thad Cochran (R-Miss.) and state Sen. Chris McDaniel.
McDaniel held a 1,400-vote edge after Tuesday night's primary with nearly all precincts reporting and just a small portion of mail and provisional ballots still out.
Neither candidate topped the 50 percent vote threshold needed to win the nomination outright, with both getting 49 percent of the vote
A third Republican in the primary, realtor Thomas Carey, drew 2 percent, enough to help push the contest to a runoff.
Mississippi political observers agree Cochran may be more vulnerable in the runoff. He'll have to grapple with waning enthusiasm surrounding his candidacy and an expected infusion of cash from national conservative groups looking to boost McDaniel.
If McDaniel wins the nomination, Democrats believe they have a shot at picking up the seat this fall, and have nominated former Rep. Travis Childers as their candidate for the general election.