Now that the Republican primary in Mississippi is headed to a June 24 run-off between U.S. Sen. Thad Cochran and state Sen. Chris McDaniel, various players are deciding whether they will play in the race over the next three weeks. The most significant announcement was provided to The Cook Political Report by American Crossroads. Communications Director Paul Lindsay gave us this statement: “Other than Alaska, we have completed our work on Senate primaries this cycle and are now focused on general elections. With the Chamber, the NRSC, and a local super PAC already backing Cochran, this is not our fight.”

Crossroads’ absence in the run-off denies Cochran’s campaign a major source of outside spending, but not everyone is staying on the sidelines and Cochran will have plenty of support. Rob Collins, the Executive Director of the National Republican Senatorial Committee, has said that the committee will “fully support” Cochran in the run-off. The NRSC’s first priority is always to support incumbent. Rob Engstrom, the national political director for the U.S. Chamber of Commerce tweeted this earlier today, “The @USChamber will stand by Senator Cochran (@ThadforMS).” There is also a super PAC dedicated to Cochran that spent heavily in the primary and can be expected to continue to do so in the run-off.