The Mississippi Senate race just went from looking like a potential free-for-all to firming up as an intense one-on-one battle between the tea party wing of the GOP and its establishment.

Sen. Thad Cochran (R-Miss.) (Photo By Bill Clark/CQ Roll Call) Sen. Thad Cochran (R-Miss.) (Bill Clark/CQ Roll Call)

Sen. Thad Cochran (R-Miss.) announced Friday that he will seek a seventh term in office. The decision came after months of speculation that Cochran might retire — speculation fueled in part by the senator's own actions. He raised little money and delayed his announcement about the future until almost the end of the year, after most of his Senate colleagues had declared their intentions for 2014.

It also came after a high-profile primary challenger emerged eager to run to Cochran's right. State Sen. Chris McDaniel announced his campaign in October and was quickly embraced by national tea party groups with a habit of meddling with their wallets in GOP primaries. The anti-tax Club For Growth, the Senate Conservatives Fund and the Madison Project are all backing McDaniel, the 41-year-old legislator who embraces comparisons to Sen. Ted Cruz (R-Tex.).

Cochran's fiscal record has stoked skepticism on the political right, making him a clear target of conservative ire.

“Throughout his over 40 years in Washington, Senator Thad Cochran has done some good things for Mississippi, but he’s also done some bad things," said Club For Growth President Chris Chocola. "He voted to bail out Fannie Mae and Freddie Mac, voted repeatedly to raise the debt limit by trillions of dollars, and even voted against a resolution that stated Congress has a 'moral obligation' to cut spending."

But Cochran's supporters say that his long résumé in the state and penchant for bipartisanship without ceding his ground will make him a very tough out next year.

"His help after [Hurricane] Katrina is legendary," said Henry Barbour, a Republican National Committee member and nephew of former governor Haley Barbour.  "He's one of the last people in Washington who knows how to stand on principle but work with folks from both sides of the aisle.  His opponent does not think much of that ability, but folks in Mississippi are proud to have Thad representing us."

The campaign will present an unfamiliar political test for both Cochran and McDaniel. Since he won his seat in 1978, Cochran, 75, has never really faced a tough electoral challenge. McDaniel, meanwhile, has only been in the state Senate since 2008, and has never gone through a race of this magnitude. McDaniel, a lawyer,  made a name for himself as a conservative talk radio host.

"I will run hard and be successful so that I can continue to serve the people of Mississippi and our nation effectively," Cochran said in a statement.

The race will also ramp up tensions within the national Republican Party. Facing a primary challenger of his own who is backed by the Senate Conservative Fund, Senate Minority Leader Mitch McConnell (R-Ky.) and his allies have leaned heavily into an effort to derail the opposition. The National Republican Senatorial Committee, for example, sought to punish a consulting firm that has worked with the Senate Conservative Fund by refusing to do business with them and urging other campaigns not to partner with them, either.

It's not just McConnell and the NRSC who are pushing back against the right. Business groups have also begun ramping up support for their preferred Republican candidates. That has put them on a collision course with the tea party. In Idaho, the Chamber of Commerce begun airing an ad this week in defense of Rep. Mike Simpson (R), who faces a conservative primary challenger backed by the Club For Growth.

Had Cochran opted for retirement, there was speculation that a host of other Republicans might jump into the race for his seat. But now, it seems like the contest in the ruby red Southern state will come down to whether a member of the old guard who is a household name can beat back a challenge from a young tea party candidate.

"I look forward to a positive campaign based on the future of our state, our country and the Republican Party," McDaniel said in a statement.

But given the stakes and the battles lines in this contest, it would be surprising if it ended up a friendly fight.