On Sunday night, resplendent in his many layers of shirts, Steve Bannon declared war on establishment Republicans. The former Wall Streeter turned right-wing propagandist is always declaring war on something or other; this is a guy who calls himself a "street fighter" and never met a military metaphor he couldn't wallow in. But this time there seems to be money where Bannon's mouth is—the former White House strategist and Trump campaign manager is reportedly backing several primary challengers to incumbent Republicans ahead of the 2018 midterms, and Bannon's support is sure to come with lots of ink from his site, Breitbart, and millions in contributions from the shadowy Mercer family, the longtime patrons of his political operations.

In Sunday's much-hyped 60 Minutes interview, Bannon made it clear why he was lashing out at his own party: "They do not want Donald Trump's populist, economic nationalist agenda to be implemented," he said, meaning GOP congressional leaders Paul Ryan and Mitch McConnell but also, presumably, mainstream Republicans in general. On his target list, reportedly, are senators Bob Corker, Roger Wicker, Luther Strange, Dean Heller, and Jeff Flake.

Bannon hasn't explained how exactly these swampy politicos halted Trump's nationalist agenda. Did they vote against the president's first major legislative priority, the repeal of the Affordable Care Act? No, other Republicans did that. Have they publicly criticized the Trump- and Breitbart-endorsed RAISE Act, which would drastically restrict legal immigration? No, again, other Republicans did that. (None of whom are up for reelection in 2018.) Have they opposed Bannon's long-dreamed-of infrastructure plan? No, since no one in the White House besides Bannon seemed at all interested in infrastructure, and no plan has been released. Did these no-good establishmentskis force Trump to back off his economic protectionist rhetoric? Nope, on issues from China to NAFTA the president has been flip-flopping all by himself.

So why go after sitting Republican senators who have been with the president on every important vote? One notion is that he's going after senators like Flake and Corker because though they've backed Trump's agenda, they've also criticized him personally, and Trumpists prize loyalty above all. But Jim Newell at Slate suspects Bannon isn't thinking about Trump or populism, but rather his own petty grudges—he's either out to punish Republicans who supported immigration reform in 2013, or simply to embarrass Senate Majority Leader Mitch McConnell, the ur-swamp dweller in the Breitbart cosmology.

All this makes Bannon's "populism" a curious thing. He loves to talk about "economic nationalism" as a way of distinguishing himself from other Republicans—a worldview that emphasizes the interests of native-born workers by restricting immigration, preserves their government benefits, and protects them from foreign competition. Bannon may believe all that stuff; he's even talked about raising taxes. But all that talk has utterly failed to turn into action.

Even after Bannon helped guide Trump to a shocking victory in 2016 and secured a plum spot at the White House, that alleged populism didn't materialize. Instead, the administration pursued a traditional Republican agenda of slashing regulations, cutting taxes, and trying to defund the social safety net. Maybe that's because Trump staffed the White House with non-Bannonites like Budget Director Mick Mulvaney (who wants to slash Social Security) and economic adviser Gary Cohn (who favors free trade). But that staffing shows how ineffective Bannon was in getting his people into key positions. Now that he's on the outside it's hard to imagine he's going to be a better advocate for that phantom "economic nationalism"—even if he brags about how much he still talks to Trump.

Scratch any of the Bannon-backed primary campaigns and you'll find that the populism he espouses is skin-deep, if that. In Alabama, where a GOP runoff election is scheduled for September 26, Bannon is supporting Roy Moore against Luther Strange, who has been endorsed by McConnell and Trump himself. But Moore is hardly part of the Breitbart wing of the Republican Party—he's an old-school homophobic social conservative who as a judge refused to grant marriage licenses to same-sex couples. In Nevada, Bannon's man against incumbent Dean Heller is Danny Tarkanian, who has remade himself recently as a pro-Trump conservative but is mostly a political wannabe with a long history of failed campaigns.

Bannon's populism isn't any less shaky when it comes to the issues in play as these elections approach. On 60 Minutes, he predicted that if establishment Republicans endorsed DACA—an Obama-era program protecting undocumented immigrants who came to the US as children—it would send the GOP into a "civil war." Breitbart has been trying to fulfill that prophecy, linking DACA recipients to the MS-13 gang with an incredibly misleading image choice and running an anti-DACA column from anti-immigration crusader Tom Tancredo.

There may be bona fide populist support for restricting immigration, especially illegal immigration, but DACA recipients are the most sympathetic undocumented immigrants you can imagine: law-abiding, hard-working, and just wanting to remain in the only country they've known. That's why polls show that few voters, even on the Republican side, want them deported. If Bannon's populism is anti-DACA, it's a very unpopular form of populism—the views of a xenophobic fringe given a megaphone by an idiosyncratic billionaire, not an actual grassroots movement.

As for whether Bannon's "war" will succeed, that's up in the air. The first battle will be in Alabama, where Moore could very well defeat the establishment's Strange—but after a bitter primary, there's a danger of either Republican being upset by the Democrat in the general election, weakening Trump even further. And as Politico noted, Breitbart supported a similar slate of insurgent candidates in 2014 and all of them lost. If that happens again, it'll hardly help Trump's nationalist agenda, or whatever remains of it. But I'm sure Bannon will find a way to stay in the news anyway.