For progressives and liberals, it is tempting to eye the current discord and disarray in the Republican Party with a sense of amusement, if not outright glee. But the current trend of divisive loyalty tests for national political candidates poses a grave danger to the nation, especially when imposed by an ally of an authoritarian administration that regularly demonstrates contempt for the institutions and norms of representative democracy.

Senator Jeff Flake was never much for Donald Trump. Flake, a libertarian, didn’t support Trump’s presidential bid, and has been a constant critic of the president since from the administration’s outset, even writing a book about how Trump is destroying conservatism (a phenomenon we noted during the primary campaign). Steve Bannon, the propagandist and former White House strategist turned kingmaker, promised to back a primary challenger to Flake, the U.S. senator from Arizona who would have been up for re-election next year. Yesterday, Flake folded, announcing, in a speech on the Senate floor, that he would not seek another term because he would not be complicit in the “casual undermining of our democratic ideals” as executed by President Trump.

If Flake uses the platform he still possesses for the next 14 months to gather other Republicans to challenge the legitimacy of the Trump presidency, that would be a good thing. But the danger inherent in the means by which Flake was pushed out of his seat poses nearly as great a threat to the republic as the Trump presidency itself, and possibly one with a much longer life.

As Prospect co-editor Robert Kuttner noted on NPR’s Morning Edition on Wednesday, Bannon may not be able to rule the Republican Party, but he can divide it. And it is through that division that Bannon can fundamentally alter the party’s DNA to favor authoritarian candidates who offer no pretense of regard for the tenets of the U.S. Constitution, or any of the norms or institutions of representative democracy. In a binary system such as ours, the republic is gravely threatened when the members of one of the two major political parties risk ouster-via-primary for insufficient loyalty to an authoritarian executive.

Bannon likes to cast his own political philosophy—and the president’s—as one of “economic nationalism,” defined by the imposition of tariffs, a retreat from an international human-rights agenda, and opposition to multilateral trade deals. But the truth is, as Kuttner writes in the Fall issue of the magazine, Bannon’s brand of “economic nationalism” feeds on what has come to be known as “white nationalism”—a noxious blend of racism and isolationism that casts so-called white culture as America’s defining characteristic. (Bannon may claim to reject “white nationalism,” but he’s been courting its proponents for years.) Such an ideology dispenses with the need for the fanciful interpretation of the U.S. Constitution that the Tea Party movement made its talisman. White nationalism has little need for the Constitution at all. White nationalists invoke the Constitution only when asserting their right to say hateful things, or to carry the lethal weaponry that was on display that awful summer day in Charlottesville, Virginia. The more power they gain, the less they need the protections of the Constitution, because their ideology stands in opposition to democracy.

Without even having to launch actual primary challenges, Bannon has already run two U.S. senators from office: Flake and Bob Corker of Tennessee, who yesterday told CNN that “the president has great difficulty with the truth.” Fear of the promised primary challenge drove men from office; neither was up for a fight he believed he would lose.

That fear is driven by Bannon’s backing of Roy Moore in Alabama’s current U.S. Senate contest—the former Judge Roy Moore, who was twice thrown off the bench of his state’s Supreme Court for having refused to uphold the U.S. Constitution. With an assist from Bannon after declaring his candidacy, Moore beat the incumbent Luther Strange in Alabama’s Republican primary, despite Strange’s endorsement by Trump and Vice President Mike Pence. By supporting Moore—who advocated against the removal of segregationist mandates in the Alabama state constitution—Bannon also put Trump and Pence on notice that the would-be kingmaker and his donors expected the administration to stay the white nationalist course, or else there would be trouble.

The message was received. At the Values Voter Summit, an annual conference staged by the political arm of the Family Research Council, the featured big-name speakers were Trump, Moore, and Bannon, who delivered a dark vision of an America facing a bloody “fourth turning” of history.

Should Bannon succeed in launching all the primary challenges he’s threatened, he may just lose a few. But it won’t really matter. The immediate contests aren’t the main act; the coin of the realm is the fear they instill in all Republicans facing re-election, both in the House and the Senate. And fear has always been the animating force of all Bannon productions, whether in the propaganda films he’s produced and written over the years, or at Breitbart.com, the hatemongering website he runs. And, as my colleague Eliza Newlin Carney writes, Bannon’s fearmongering in congressional elections stands to make him an even richer man than he is already.

Absent a critical mass of opposition to Trump from among Republicans in Congress, Trump will remain in power. The longer he remains in power, the more time Bannon will have to reshape the GOP in his white nationalist image.

On Tuesday, Military Times, which covers the military for a readership comprising mostly members of the armed forces, released a poll of service members, who rated “white nationalism” as “a larger national security threat than Syria, Iraq and Afghanistan,” according to a report on the Military Times website. And 1 in 4 troops said they had seen evidence of white nationalism in the ranks.

Viruses grow by injecting their DNA into the cells of a host body, converting those cells into likenesses of the virus itself. The white nationalist virus is infecting major segments of the U.S. body politic and the institutions that maintain democracy.

To stop it will require vigilance and aggressive action on the part of every American who cares about equality and justice for all, Republican and Democrat alike. There is ample cause for Trump’s removal from office. Now that every Republican is threatened with a primary challenge for the simple sin of incumbency, there’s no reason for members of the Grand Old Party to restrain themselves in the face of the president’s criticisms—unless they really don’t care about the fate of the republic.

It really is just that simple.