Just a couple of months ago, Republicans viewed Thad Cochran as the most likely senator to retire in 2014. But now that he’s seeking a seventh term, the Mississippi senator has more work to do than any other Republican in his chamber.

Cochran must pull the tarp off his dusty political operation to defeat a tea-party-backed primary challenger, state Sen. Chris McDaniel. That includes staffing up, reaching out to longtime party insiders across the state and kick-starting fundraising ahead of his primary, which is less than five months away.

On Capitol Hill, Cochran is wielding his seniority as a political tool. He has reasserted his authority on certain issues — especially on a stalled farm bill that some believe he is holding up largely on his own. As the top Republican on the Senate Agriculture Committee, Cochran has taken a more aggressive stand to protect the parochial interests of Mississippi since he announced his re-election bid.

Agriculture Chairwoman Debbie Stabenow, D-Mich., and her House counterparts, Frank D. Lucas, R-Okla., and Collin C. Peterson, D-Minn., want desperately to finish the farm bill. But Cochran has been the odd man out, dragging out the conference process with his objections to proposed changes to laws regarding catfish and farm manager subsidies.

Though catfish farming, labeling and regulation might seem trivial, it’s not to Cochran and the Magnolia State — home of Mississippi State University’s Thad Cochran National Warmwater Aquaculture Center and a billion-dollar catfish industry. Cochran appears willing to thwart the entire farm authorization bill over the measure, much to the chagrin of his colleagues but to the potential benefit of his re-election.

“Argh! I think he’s holding up the whole bill, I’ve heard,” Sen. John McCain, R-Ariz., said, before adding that he is not a farm bill conferee.

“It’s crazy,” McCain continued. “It’s a pure protectionist measure to preserve the catfish industry in Mississippi and the South, OK? And so, I said, look I’m interested in my constituents being able to buy catfish at a lower price than when there’s no competition.”

McCain called the catfish fight “outrageous and sometimes entertaining” but declined to say whether Cochran has intensified his efforts since launching his re-election campaign.

When asked to address the criticism of his colleague on the issue — and McCain certainly is not alone in it — Cochran defended his position.

“So what?” Cochran said. “I’m here to represent the interests of my constituents. And we have a strong and important part of our economy that’s based on farm-raised catfish. And those constituents are disappointed when our government doesn’t insist on at least requiring disclosure of what the American people are buying in supermarkets and stores.”

Cochran also does not believe he needs to take a special stand now as part of an additional case to Mississippians about the power he has accrued over decades of service.

“It’s my job. I’m here to represent the interests of my state and make sure people are being treated fairly, just like every other state, as well,” Cochran said. “It’s not limited to Mississippi.”

Mississippi received $8.16 billion in federal farm subsidies from 1995 to 2012, ranking it 13th in the nation, according to the Environmental Working Group.

A source tracking the farm bill also pointed to a farm manager provision included in both the House and Senate farm bills. The measure would more strictly define who is a “farm manager” and is eligible to receive payments, in order to weed out abuse of the system by people who are not actively farming. The source said Cochran did not contest the issue until 2014.

This farm bill battle comes as Cochran faces arguably the most competitive primary challenge of any incumbent this cycle.

His re-election campaign started in earnest this month, as the candidate-filing deadline on March 1 and the primary on June 3 approach. With endorsements from some of the top Republicans in the state, Cochran hired Gov. Phil Bryant’s chief of staff, Kirk Sims, as his campaign manager. He also recently added Rep. Alan Nunnelee’s, R-Miss., communications director, Jordan Russell.

Republican leaders in Washington are clearly aware of the primary threat to the media-shy Cochran. He was chosen to deliver the Jan. 11 GOP weekly address and used the occasion to attack the president’s health care law.

And Cochran is wasting no time getting out on the trail. When the Senate recesses next week, he has a full slate of campaign events planned around Mississippi, including fundraisers and public events.

“Sen. Cochran’s campaign is up and running full steam already,” said John Keast, a lobbyist and former chief of staff to Sen. Roger Wicker, R-Miss. “People from around Mississippi are signing up to help Thad in any way they can.”

Several conservative outside groups are intent on ousting Cochran, who they believe has not fought hard enough to defund Obamacare.

The groups, including the Club for Growth, Senate Conservatives Fund and the Madison Project, began airing TV and radio ads as soon as McDaniel launched his campaign in October. After working to increase the challenger’s name identification in the initial spots, they’re likely to soon turn their focus on Cochran.

McDaniel has taken every opportunity to hit the senator for voting on appropriations measures, complicating Cochran’s argument by attempting to make any of these parochial fights seem “liberal” in comparison to his tea party stance.

He released a statement Tuesday urging Cochran to vote against the “disastrous” bipartisan omnibus bill crafted by the House and Senate Appropriations committees. Of course, if Cochran wins and the GOP takes back the majority, he would be in line for the Appropriations Committee chairmanship.