Acting like a barbarian leader outside the city gates -- which he pretty much is -- Steve Bannon this week gave the Republican establishment an ultimatum:

Surrender, or die.

Or to put it into an American context, he is General Santa Anna, demanding the surrender of the defenders of the Alamo and promising no quarter if they refuse.

"We are declaring war on the Republican establishment that does not back the agenda that Donald Trump ran on," Bannon told Sean Hannity.

"Corker, McConnell, Corker and the entire clique -- an establishment globalist clique on Capitol Hill -- have to go. The globalist clique on Capitol Hill has to go,” Bannon said.

"There’s a new game in town. We are to cut off the oxygen to Mitch McConnell. Mitch McConnell’s biggest asset is the money. We’re going to make it the biggest liability. We are going after these guys tooth and nail.... Even safe incumbents like (Wyoming Sen. John) Barasso and Deb Fischer (of Nebraska) – they have to understand something. Just voting is not good enough. You have to have a sense of urgency. Nobody’s safe. We are coming after all of them and we are going to win."

According to Bannon, he and his movement will field challengers against every incumbent Republican senator except Ted Cruz of Texas, which is an irony in its own right. Barely a year ago, it was Cruz who ostentatiously stood as the last man between Trump and the GOP nomination, who attacked the GOP frontrunner as "utterly amoral," a "pathological liar," "a narcissist at a level I don't think this country's ever seen" and "a serial philanderer."

My, how the worm has turned. As Bannon suggests, it is Cruz who has since "bent the knee" to Trump to such a degree that he alone has been exempted from the holy war. Orrin Hatch of Utah, Jeff Flake of Arizona, Dean Heller of Nevada ... all must surrender or die.

The terms of that surrender are clear as well. Candidates who seek the Bannon/Hannity seal of approval -- Bannity, anyone? -- must pledge to vote against McConnell as majority leader, must pledge to abolish the Senate filibuster and must pledge total fealty to Trump and his movement, as Bannon seeks to define that movement.

That last point is critical.  What Bannon is attempting is to capture the GOP citadel and remake the Republican Party in the image of Trump, as Bannon himself defines that image.  This campaign is directed not merely at Republican senators and the Republican establishment, but at the White House and at Trump himself.  On issues such as immigration and trade, Bannon is attempting to give Trump no wriggle room, no ability to deviate from the course that Bannon sets.

And if you want to understand Bannon's end game and the lengths that he will go to attain it, I highly recommend this piece from Buzzfeed, based on reams of authenticated memos and emails leaked from Bannon's base of operations at Breitbart.  This is the vision that Bannon is attempting to impose on the GOP; this is the price that he will impose on those who choose to submit rather than fight back.