Sen. Thad Cochran (R-Miss.) hasn't announced his reelection plans yet, but the opposition is already gearing up.

Senate Conservatives Action, an arm of the Senate Conservatives Fund, is making a $263,000 ad buy in the state on behalf of its endorsed candidate, state Sen. Chris McDaniel (R), according to information shared with Post Politics.The ad features footage of McDaniel's campaign launch, pitching his message of conservatism. It will air for two weeks on broadcast and cable television.

Cochran has said he will announce by the end of the month whether he will seek another term. The ad could be seen as an effort to send a message to Cochran -- and anybody else who might run if he retires -- that at least one conservative group is prepared to spend real money on McDaniel in the primary.

McDaniel has also gotten the backing of several other conservative and tea party groups: the Club for Growth, FreedomWorks, the Madison Project and the Tea Party Express.

Other Republicans who might be interested in Cochran's seat include Mississippi Secretary of State Delbert Hoseman, state Auditor Stacey Pickering, Rep. Gregg Harper and Lt. Gov. Tate Reeves.

Update 3:39 p.m.: According to Senate Conservatives Action's FEC filing, the ad was filmed by Jamestown Associates -- a group the National Republican Senatorial Committee is reportedly discouraging campaigns from hiring due to its work for the conservative group. Two new consulting groups also appear on the filing: Red Sea LLC, which produced the ad, and Target Enterprises LLC, a media buyer.