Steve Bannon’s financial benefactor, Republican mega-donor Robert Mercer, moved Thursday to distance himself from the nationalist firebrand, but it was unclear if that indicated a break in their alliance.

A political operative close to Bannon, chairman of Breitbart News, said that Mercer’s decision to sell his share of the insurgent conservative news website to his daughters was intended to facilitate closer coordination between the two ahead of 2018.

“This is all about Robert Mercer going all in with Steve. He’s going to be more engaged with Steve politically,” this source told the Washington Examiner.

Bannon, President Trump’s former chief strategist, is recruiting candidates and raising resources to challenge incumbent Republicans in primaries next year.

His primary goal is to alter the makeup of the Senate and oust the chamber’s majority leader, Sen. Mitch McConnell, R-Ky. Mercer has already donated to at least one of Bannon’s candidates, Kelli Ward, the Republican running for Senate in Arizona, who was challenging Sen. Jeff Flake in a primary until the incumbent announced his retirement.

McConnell and his allies have responded with brass knuckles. They’re highlighting Bannon’s associations with figures on the “alternative right,” some who have expressed racist views, and recycled reports from 2016, when he ran Trump’s campaign, about his alleged anti-Semitism.

In that light, Mercer’s letter to the employees of the New York hedge fund he runs announcing his retirement and setting the record straight on his political views could appear as a reconsideration of his association with Bannon, possibly a decision to yank funding for his insurgency.

That would be significant. Despite Bannon’s media savvy considerable political acumen, he would be just another operative with an opinion without Mercer’s money, said one Republican consultant.

“Mercer is the difference between the bark and the bite for Bannon,” this operative said, on condition of anonymity in order to speak candidly.

Mercer in his letter said he regretted his support for former Breitbart writer Milo Yiannopoulos, a controversialist who has surrounded himself with white supremacists. He also made clear that he does not always agree with Bannon.

“The press has also intimated that my politics marches in lockstep with Steve Bannon's. I have great respect for Mr. Bannon, and from time to time I do discuss politics with him. However, I make my own decisions with respect to whom I support politically. Those decisions do not always align with Mr. Bannon's.”

McConnell's low approval numbers could boost Bannon's campaign, as GOP incumbents are cornered about whether they would continue to support him as majority leader. But Bannon faces a host of challenges in prosecuting an effective insurgency against the GOP’s establishment figures, even with Mercer’s money.

Ward, his candidate in Arizona, recently suffered public staff defections. They issued a press release apologizing for their participation in her campaign and said she wasn’t worthy of being nominated — this was prior to Flake retiring.

Foster Friess, a deep-pocketed GOP donor in Wyoming, was being recruited by Bannon to challenge Sen. John Barrasso, the fourth-ranking party leader in the Senate and a McConnell ally. But Friess ultimately rejected Bannon’s entreaty and vowed to work against him if necessary.

Meanwhile, in some states, Bannon is joined at the hip with the establishment, backing some of the very candidates they recruited to run for Senate. Josh Hawley, the state attorney general running for Senate in Missouri, is one example.