Steve Bannon is looking to Alabama’s upcoming Senate primary as the opening salvo in his war against establishment Republicans — one whose results could be a major factor in determining just how scared GOP incumbents are of his political power.

Bannon, Trump’s former chief strategist, is using his rabble-rousing website Breitbart as a megaphone to promote controversial former Alabama Supreme Court Chief Justice Roy Moore (R) over appointed Sen. Luther Strange (R-AL), who Senate Majority Leader Mitch McConnell (R-KY) is backing with all his might.

Two sources close to Bannon say with Moore leading the race just two weeks out from primary election day, Bannon sees an opportunity to take credit for an early scalp and scare Republican incumbents into ending their burbling criticism of the President.

“Steve views this as the flashpoint in his national war against McConnell,” said one source close to Bannon. “We’re sick and tired of these Senate and House Republicans thinking they can get away with a free shot at the President without facing any consequences.”

With two weeks to go until the Sept. 26 election, both Bannon and McConnell have a lot riding on the race.

A Moore win would send shockwaves through Washington, spooking Republicans and showing that McConnell’s money can’t save them from a wrathful populist base even when President Trump isn’t fueling that fury (he’s given Strange a tepid endorsement). A come-from-behind Strange victory, on the other hand, would show Republican lawmakers that McConnell’s deep pockets may matter more than Bannon’s pugilistic ability to turn Trump’s core voters against incumbents—and they might grow more willing to publicly criticize the President as a result, leaving both him and Bannon increasingly isolated.

“If Strange pulls this race off in Alabama that carries some good ramifications. If he doesn’t all these guys are going go back in their corners, scared of being the next Luther Strange,” said former Rep. Tom Davis (R-VA), an establishment Republican who helmed the National Republican Congressional Committee.

“It’s a canary in the coal mine for Senate and House Republicans that the mood in Washington is broken and needs to be fixed, and anything different than that means you’re going to be running into a headwind,” said another Bannon ally.

Bannon and a close ally working for a pro-Trump outside group, former White House staffer Andy Surabian, sat down with Moore and his campaign staff at Bannon’s mansion late last week in a series of meetings with potential primary challengers, two sources confirmed to TPM. It’s unclear whether or not they’ll come in with any money to help the underfunded Moore in the campaign’s home stretch, but helping amplify his message on the far right could pay dividends for both sides.

McConnell hasn’t been as loud about his Strange support, but he’s put a lot of money where his mouth is. He recently headlined a D.C. fundraiser for Strange, and a super-PAC run by his allies has spent millions of dollars to knock down Moore.

Bannon made it clear in an interview that aired Sunday on CBS’ “60 Minutes” exactly what he thinks of McConnell and House Speaker Paul Ryan (R-WI).

“The Republican establishment is trying to nullify the 2016 election. That’s a brutal fact we have to face,” he said, calling out McConnell and Ryan by name and saying they “do not want Donald Trump’s populist, economic nationalist agenda to be implemented.”

Breitbart-led campaigns against sitting incumbents are nothing new, and more often than not have come up short. Ryan easily dispatched a Bannon-backed primary foe last year, and McConnell-backed candidates managed a perfect winning record against a bevy of ring-wing challengers in 2014 and 2016. But Bannon never before had the ear of the sitting President. Trump remains immensely popular with the base and is already causing some big-league problems for incumbents who’ve dared cross him, including Sens. Jeff Flake (R-AZ) and Dean Heller (R-NV), both of whom are in Bannon’s crosshairs and face tough Trump-fueled primary challengers. Sen. Bob Corker (R-TN) also said Monday he’s mulling retirement, though he insisted a Bannon-backed primary challenger wasn’t playing in his reasoning. Sources close to Bannon say he may back a number of challengers to House Republicans.

“McConnell ran the table against conservatives running against incumbents, but he didn’t have a Republican President. And now Donald Trump is at the top of the organizational chart, not Mitch McConnell,” said the second Bannon ally.

Ironically, Trump endorsed Strange during the first round of the primary, a move sources close to the White House have told TPM was more about getting revenge on Rep. Mo Brooks (R-AL), who was in the race and had criticized Trump, than about doing a favor for McConnell.

Trump and McConnell are on even worse terms now than they were back then, and the President’s only public comment on the race since the first round of voting was a tweet congratulating both Moore and Strange on making the runoff.

Congratulation to Roy Moore and Luther Strange for being the final two and heading into a September runoff in Alabama. Exciting race! — Donald J. Trump (@realDonaldTrump) August 16, 2017

A source close to the White House tells TPM the White House recently conducted a poll showing Moore comfortably ahead in the race, dissuading Trump from doing anything more for Strange. Politico also reported Monday that Trump had promised Strange an in-state rally that he’s no longer planning to do.

Strange’s team said given the ongoing hurricane fallout, they’re not pressing the White House for more help at this time. But they’re milking Trump’s endorsement for all it’s worth. Strange debuted a new campaign ad Monday touting Trump’s support, a shift from a bevy of attack ads he’s been leveling against Moore:

Moore has led all public polls, and while some have shown a double-digit blowout for him, others have found Strange within striking distance. Moore’s Trumpian anti-establishment career and loyal fanbase among hardline evangelicals are why he’s leading the race, not Bannon’s backing.

“What do you think Breitbart’s name ID is in this state, five percent?” asked Tom Young, a former Shelby chief of staff who’s backing Strange.

Strange has struggled thanks to the one-two combo of having been appointed by a corrupt former governor he’d been investigating and the support of the deeply unpopular McConnell. But Strange’s allies insist it’s going to be a photo finish.

“Let’s see who turns out. I think it’ll be a close race,” Sen. Richard Shelby (R-AL) told TPM.

But perceptions of power sometimes matter more than reality in scaring politicians. And Bannon’s anti-Strange attacks are just a sign of what’s to come. In future races, he’s more likely to be able to count on Trump and big money from Trump super-donors Robert and Rebekah Mercer to make more noise, forcing incumbents to spend scarce resources on nasty primaries.

“I wouldn’t be afraid of Bannon. But what they do is bring outside money with these super-PACs. I don’t think you cower to them but they have to use a lot of resources,” said Davis, warning that if Moore wins, “members will look over their right shoulder. It probably has that effect.”

TPM composite via Christine Frapech. Images via AP.