Jeff Flake saw the writing on the wall.

Republican senators stood on the floor of the Senate Tuesday afternoon in a somber display, giving Flake a standing ovation as he announced his retirement in a searing speech criticizing President Donald Trump.

Meanwhile, Steve Bannon, the former White House chief strategist, seemed overjoyed. "Another day, another scalp,” was his reaction, according to a source close to him interviewed by NBC News.

Incumbent Republican senators are increasingly under fire from the right. Flake was trailing a primary challenger by about 25 points in polls before he called it quits. Sen. Bob Corker (R-TN), facing a potential primary threat of his own, announced he’d retire too. And appointed Sen. Luther Strange (R-AL) went down to defeat during a primary runoff against outsider Roy Moore.

All three had been targeted for defeat by Bannon, as part of what he recently called his “war against the GOP establishment.” And there are more to come. There will be at most six incumbent Republican senators on the ballot next year. Bannon hopes to target five of them. “They’re heading into a titanic political fight,” says Steve Schmidt, who ran John McCain’s presidential campaign in 2008. “And they underestimate it at their peril.”

One Republican consultant with ties to Senate leadership characterized Bannon’s effort as incoherent. “He’s almost like a mad dog chasing a car who doesn’t know why he’s chasing it,” the consultant said.

But conversations with conservative activists, GOP operatives, and people close to Bannon and the White House suggest that the Breitbart executive chair is engaged in a bold, ambitious project that has a relatively clear vision. He doesn’t just want to destroy the old Republican establishment — he wants to build a new one.

To do that, he hopes to unite many factions of the right who have gripes against GOP leadership into a broad coalition. That would include immigration hardliners who fear “amnesty” deals. But it would also include social conservatives and anti-spending activists who feel their priorities are too often ignored or compromised away.

Overall, he wants Republican senators to care far less about what the Chamber of Commerce thinks, and far more about what Breitbart readers think.

A source close to Bannon describes his basic pitch to all these disparate groups as a simple one: “The elites have failed us.”

The targets: almost every incumbent Republican senator

The grandiose project of reshaping an entire major political party has to start somewhere, and for Bannon, it will start with the United States Senate.

The vast majority of the Senate’s 52 Republicans tend to be willing and eager to work with their party’s leadership rather than defy it. In contrast to the House of Representatives, where the well-organized Freedom Caucus often foils party leaders’ plans, there are only a handful of loose-cannon senators.

Most Republican senators are instead like Roger Wicker, a Republican from Mississippi. Genial and white-haired, Wicker has been in elected office for three decades, and yet rarely makes national headlines. He’s a conservative who stands staunchly behind President Trump on any matter of note. There are few heresies in his record that activists on the right can criticize him for. In many ways, he’s a perfectly ordinary GOP senator.

He’s exactly the sort of senator Bannon wants gone. Indeed, the only Republican senator on the ballot in 2018 whom Bannon wants to return is Ted Cruz, whom he’s deemed sufficiently anti-leadership and anti-establishment. Everyone else in the party running — everyone else happy to work closely with Mitch McConnell — is a target. Besides Wicker, they are Sens. Dean Heller (R-NV), Deb Fischer (R-NE), John Barrasso (R-WY), and Orrin Hatch (R-UT), should the 83-year-old choose to run again.

None of these five have been consistent critics of President Trump. But they also aren’t very much like President Trump stylistically. They aren’t fire-breathing outsiders eager to tear down the current system, or culture warriors eager to anger liberals and elites.

“The day of taking a few nice conservative votes and hiding is over,” Bannon proclaimed to them in a recent speech to the Values Voter Summit.

He wants politicians who are hardliners on immigration — who would agitate against any deal to legalize the status of unauthorized immigrants. (DREAMers, he recently said, should “self-deport.”) He wants politicians who aggressively stoke cultural resentments against those he characterizes as liberal globalist elites.

And he wants, he’s said, to make Mitch McConnell so “toxic” that he’ll be forced out of leadership.

The weapon of choice: primary challenges

Of course, you can’t beat something with nothing, so much of Bannon’s effort will hinge on the quality of the challengers he backs. And these possible challengers currently look, as Karl Rove recently put it, like “a motley crew,” with wildly varying backgrounds, strengths, and weaknesses.

In Nevada, Danny Tarkanian, best known for losing several elections over the past decade, is now trying his luck against Heller.

A likely candidate in Mississippi is Chris McDaniel, a Tea Party favorite who came within a hair’s breadth of unseating incumbent Thad Cochran in 2014.

In Utah, Boyd Matheson, a former chief of staff to Sen. Mike Lee, is being discussed as a possible candidate — but it’s not clear whether, if he does run, Bannon will back him.

In Wyoming, Blackwater founder Erik Prince is considering a run, but while he is certainly very rich, his electoral appeal is untested.

Finally, Nebraska is a question mark — a recent Omaha World-Herald report found puzzlement among conservatives there about why anyone would want to challenge Fischer from the right, and who would possibly do it.

In some ways, however, the mere fact that challengers are running and will get some support is itself the point. Bannon wants to make even ordinary, reliable conservative Republicans look over their shoulders in fear of tough primaries, so they will pay more attention to what their base voters think — or else retire.

It’s a bold strategy, and a risky one. Successful Senate primary challenges are rare. In hundreds of Senate elections since 2003, a mere six incumbents running again have lost renomination — and two of them, Joe Lieberman and Lisa Murkowski, ended up winning their general elections anyway. And there is of course the added risk that a more extreme primary victor could lose the general election to a Democrat, as McConnell has warned.

But the primary challenge can be an incredibly powerful, party-reshaping tool. After all, every incumbent, even those in the safest general election seats, must get through the primary. Plus, they have to get through it first — meaning primary base voters may often weigh more urgently on politicians’ minds than general election swing voters.

Furthermore, it can work as a kind of force multiplier. High-profile, attention-getting successes in one primary race — such as then-House Majority Leader Eric Cantor’s shocking defeat in 2014 — can strike fear into the hearts of hundreds of other incumbents. Senate primaries, which Bannon plans to focus most on in 2018, have a similar narrative-setting power.

Already, incumbent politicians’ intense and growing fear of primary challenges has done much to polarize US politics, and to make bipartisanship less likely. And now Bannon wants to amplify the power of the primary, and the fear it causes, even further.

The strategy: unify the anti-establishment right

Take Roy Moore. The former chief justice of the Alabama Supreme Court, Moore had a history of fringe views and seemed most passionate about matters of religion. But he was very clearly an outsider whom the GOP establishment desperately didn’t want in the Senate. He also had a support base among evangelical voters in the state, and looked like he could embarrass party leaders. So Bannon backed him.

This illustrates the case-by-case approach Bannon is using to evaluate challengers in all these races. He very much wants candidates who will share his hardline views on immigration, and who will be more skeptical of trade deals. But because he’s trying to build a big tent, not every challenger will share his full set of policy preferences.

For instance, Bannon has said he’d prefer economic policies that conservatives generally consider far more heretical. “The conservatives are going to go crazy. I'm the guy pushing a trillion-dollar infrastructure plan,” he told journalist Michael Wolff last year, shortly after he’d been named chief strategist for the incoming White House. And while in the job, word leaked out that he was privately pushing for Trump’s tax plan to include higher taxes on the wealthy. But he does not seem to have found candidates who share his views on those matters.

Henry Olsen — a fellow at the Ethics and Public Policy Center and a savvy observer of GOP politics and voting coalitions — thinks that’s no accident. “Bannon’s very clear that he thinks the default Republican view, which he calls the establishment, is both politically and morally wrong and he means to smash it,” says Olsen. “But he cannot succeed without the tacit cooperation of the hard right.”

Olsen believes there simply aren’t enough “populists” who vote in Republican primaries and have sufficient institutional strength to create a consistent winning coalition across the country. Essentially, Bannon needs more allies.

And among his most likely allies are the economic conservative politicians and activist groups that for years have bedeviled the GOP leadership by demanding hardline tactics to try to force deep tax cuts and spending cuts, especially to the welfare state. “So what’s interesting is that to win a Republican primary, he’ll have to align with groups that are further away from what he wants on economics,” Olsen says.

This helps make more sense of, for instance, why Bannon has gotten along so well with the leaders of the House Freedom Caucus this year. Even though they’d never in a million years back massive new federal spending on infrastructure, they share Bannon’s anti-Republican leadership mentality and his yearning to more deeply disrupt Washington’s status quo.

Many of these economic conservatives also want a harder line on immigration and tougher scrutiny of how trade deals are crafted — like Ted Cruz. They are following their voters. “On the policy front, I think immigration is going to be the key,” says a Republican consultant with ties to the Trump White House. “In Republican primaries, there is no constituency for supporting immigration reform.”

Notably, Bannon needs money to fund these campaigns too, and he’s hoping to raise a good deal of it from ideological megadonors. (In the Values Voter Summit speech, Bannon swiftly pivoted from trashing McConnell’s big fundraising for Strange to taunting McConnell that “the donors are not happy” with him.)

Reportedly chief among these big donors are hedge fund manager Robert Mercer and his daughter Rebekah. The Mercers have long been close to Bannon — they invested in Breitbart and have hosted Bannon on their yacht. They too have long distrusted the GOP establishment and seem to think it’s about time for new blood.

There’s some hesitancy among some free market activists about aligning with Bannon. “Conservatism is not this nationalist populist bullshit. A conservative believes free markets are best for human liberty,” one conservative strategist recently fumed to me. “This is a fracturing of the Republican Party — a further fracturing of what conservatism is.”

But Bannon’s actions in recent months suggest that he hopes to put whatever differences he has with conservative groups aside, to unite one anti-establishment coalition. This is why he appealed to the Values Voter Summit — a confab for the religious right — trying to enlist them in “our war” against “the establishment.” This is why he reportedly hopes to install an ally at the Heritage Foundation, the leading conservative think tank he once viewed as an enemy.

The message: run against Mitch McConnell

Bannon’s challengers plan to rely on a message that could prove very appealing in GOP primaries: They’ll say they’re President Trump’s truest supporters and friends, who are merely trying to drain the swamp by getting rid of Mitch McConnell.

At a rally for Moore last month, Bannon hammered this message home, stressing that Moore’s opponent Luther Strange was the majority leader’s candidate. “Mitch McConnell and his permanent political class is the most corrupt, incompetent group of individuals in this country!” he said. “They think you’re a pack of morons. They think you’re nothing but rubes. They have no interest at all in what you have to say.”

But he emphasized that President Trump — who is quite popular among GOP primary voters — isn’t a part of that group of corrupt political elites. “We did not come here to defy Donald Trump, we came here to praise and honor him,” Bannon said.

It sounds reasonably plausible. Trump himself has harshly criticized McConnell this year for failing to pass big bills. “I’m very disappointed in Mitch,” the president said this summer, calling the Senate’s failure to pass a health bill “a disgrace.”

But while Bannon is reportedly encouraging Senate challengers to support ending the legislative filibuster, something that would make legislation easier to pass, there’s an element of opportunism to his critique too. In most cases, replacing leadership-loyal generic Republican senators with independent outsiders would likely make it harder for the Senate to get bills to Trump’s desk, not easier.

Somehow, though, Trump’s own endorsement of Strange ended up seeming like an unimportant footnote in the Alabama race. The power of Moore’s outsider status and his anti-McConnell message helped propel him to victory, and the GOP nomination. Vice President Mike Pence even admitted this after Moore’s win. He tweeted, “We are thrilled you ran on the #MAGA agenda & we are for you!”

It remains to be seen whether that line of argument will be successful for candidates elsewhere who might lack Moore’s preexisting support base. But if the majority leader’s name has indeed become mud in GOP primaries, watch out.

The endgame is still unclear

Bannon’s top stated target may be McConnell, but he can’t make a direct attempt to get rid of him until 2020, when the Kentuckian is up for reelection. McConnell was reelected as leader unanimously by Republican senators last November, so he’ll likely be reelected next year too. Overall, he doesn’t appear to be going anywhere anytime soon. “We've got a long haul in front of us,” Bannon recently acknowledged to the New York Times.

Still, all this criticism is taking a toll — the Hill surveyed two dozen Republican Senate candidates about whether they’d support McConnell as leader, and none responded with a clear yes. His approval ratings in Kentucky look dismal, and his primary in 2020 could be ugly should he run again (he’ll turn 78 that year).

However, if Bannon does end up with McConnell’s scalp, it’s not necessarily clear that his replacement would be much of an improvement. Even if many of his challengers win this year, the GOP Senate conference would still be a long way away from a majority of outsider populists. Plus, it’s widely expected that if McConnell does exit, either his No. 2, John Cornyn (R-TX), or his No. 3, John Thune (R-SD), would take over as GOP leader.

Even in the fantasy world where Bannon and his allies somehow topple the full Republican leadership team, it is unclear just how things would change. True, Bannon himself would clearly become a kingmaker and enhance his influence within the party. But electing a slate of fire-breathing outsiders could well make it even more difficult for Republican senators to accomplish anything.

And then there’s the question of whether Bannon’s hoped-for alliance with the economic right in fact makes sense. Olsen argues that an underrated factor in Trump’s appeal to the voters he won over was his opposition to cuts to the safety net. But if Bannon helps elect more candidates with Freedom Caucus-like views — who want to, for instance, deeply cut Medicaid — it could well set up “a Congress that moves farther away in some aspects from the Trump Democrat view of the world,” Olsen says.

But these are problems for later. For now, Bannon’s next step looks clear. “Bannon isn’t looking to compromise with Ryan and McConnell,” says Schmidt. “He’s looking to take them out.”

“You can’t appease it,” he continues. “One side will win.”