Donald Trump and Michael Flynn are collaborating again.

No, the president and his former national security adviser aren’t formally working hand-in-hand. Nor are they on the same team.

But as Trump continues to wage an all-out war on Montana’s Democratic Senator Jon Tester for the Senator’s role in derailing White House physician Ronny Jackson’s bid to serve as the next Secretary of Veterans Affairs, Flynn is set to go after the Montana Democrat from a different vantage point.

The retired Lieutenant General, who pled guilty to lying to the FBI while serving the Trump administration, will be hitting the campaign trail this coming week. And he will be doing so for Troy Downing, a Republican businessman and Air Force veteran competing to win the Republican nomination, next Sunday in Billings. This is the second time that Flynn has appeared at a campaign event for a Republican candidate this year. Previously, he spoke at an event for GOP candidate Omar Navarro, who is mounting a longshot bid to defeat Rep. Maxine Waters (D-CA).

While Flynn is not exactly an in-demand hype man for Republican candidates across the country, his status as the most prominent victim of Robert Mueller’s probe has given him a certain cachet within Trump-loving circles.

“I think it’s great Gen Flynn is hitting the campaign trail,” former Trump campaign adviser Michael Caputo told The Daily Beast. “Deployed judiciously in districts where we need the base activated, the General could serve the President valiantly once again. And the way the Russia investigations are fizzling, he could be the Republicans’ secret weapon in the fall.”

Downing said that he was excited to have a fellow former service member drum up support for him in his bid to unseat Tester.

“General Flynn is a patriot who has put 30 years of service into this nation,” Downing told The Daily Beast in an interview. “That resonated with me. One of the issues that General Flynn and I share is we have too many career politicians mucking things up in D.C. I think he’s excited about sending another combat veteran to D.C and start cleaning up that mess.”

Downing was unconcerned about Flynn’s guilty plea to the charge that he misled FBI agents about conversations he’d had with Russia’s ambassador to the United States, as well as and Flynn’s agreement to cooperate with special counsel Robert Mueller’s investigation into the Trump campaign and potential collusion with Russian government officials.

“He was doing what he believed was in the best interest to this nation,” Downing said. “I think he got caught up in a mess.”

Describing the probe in general, the candidate said “Obviously it’s gone on too long. I think it’s time to move on. I believe that it has been for a large part a witch hunt.”

In entering the Montana GOP primary, Flynn is crossing paths—albeit at a distance—with the president he briefly served. Trump’s increasing acrimony towards Tester, one of ten Senate Democrats up for reelection in a state Trump won in 2016, has put heightened focus on the election and raised conservative hopes of flipping the seat.

Downing recently shared a message he received from Flynn on his Twitter page that largely mirrored Trump’s recent statements. "Tester’s actions to denigrate ADM Ronny Jackson are what is wrong with WASHINGTON DC. I was glad to see the #POTUS go after him this morning,” Flynn’s message read. “My son and I are very much looking forward to coming up to help you win."

Flynn Jr. has also tweeted about his excitement to join Downing on the trail.

But despite the high-profile endorsement, Downing’s path to the nomination might not be so simple. Montana state auditor Matt Rosendale has been viewed as a favorite to compete against Tester in November. At a recent candidate forum, there was little daylight between their ardent support for the administration. Yet former Billings judge Russ Fagg did express concern about certain national endorsements in the race, specifically former White House adviser Steve Bannon’s backing of Rosendale.

“Steve Bannon is all in for Matt, and that even troubles me more than Michael Flynn,” Fagg reportedly said.

Neither Fagg nor Rosendale immediately returned requests for comment from The Daily Beast.

How exactly Flynn is choosing which candidates to back this year is somewhat of a mystery. Navarro said that he had met Flynn at the Conservative Political Action Conference in Washington D.C. and that their friendly interaction led to his endorsement. Downing told The Daily Beast that a mutual friend told Flynn about his campaign and the two men had a conversation before Flynn was invited to Montana.

“He told me you’re going to win this primary and you’re going to defeat Tester,” Downing said.

One close friend of Flynn’s, Michael Ledeen, who co-authored the book Field of Fight with the former Lieutenant General, told The Daily Beast that they speak frequently—but not about Flynn’s dabbling with campaign politics.

“We talk about the world, we talk about grandchildren,” Ledeen said. “We both have relatively new grandchildren.”

Similarly, he claimed, they don’t talk about Flynn’s case or Mueller either.

Flynn himself doesn’t appear interested in engaging with the subject on the stump either, relegating attacks against the special counsel to the president himself.

During his appearance on behalf of Navarro in March, the former national security adviser sounded like any other political figure boosting a candidate.

"What I'm not here to do is complain about who has done me wrong, or how unfair I've been treated, or how unfair the entire process has been—it is what it is, and my previous statements stand for themselves," Flynn said. "I'm here to talk about the future—your future, our future, the future of this country. If you feel passionate about something, and feeling sorry for yourself will keep you from achieving that destiny, then I can't be a part of that.”