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As Robespierre and Trotsky perhaps reflected in their final moments, all revolutions end up eating their own. Today’s cultural revolutionaries of the American left haven’t—yet—turned on their former allies with quite the same vigor as did their Jacobin and Bolshevik forebears, but the signs are there and Mark Zuckerberg especially could be forgiven for starting to feel a little figurative tightness around the throat.

Few companies have done more for Joe Biden than Facebook. After it was furiously indicted by Democrats on the fatuous charge that its facilitation of Russian meddling handed Donald Trump the 2016 election, the company went out of its way to atone. In the weeks before the presidential election last year it helpfully blocked stories about Mr. Biden’s family that were inconvenient to the Democratic candidate. It has dutifully policed and removed content that dared deviate from the administration’s official lines on Covid and other matters. It is a proud standard-bearer in the vast army of corporate wokeness. It banished Mr. Trump.

But no good deed goes unpunished, and it’s looking as though the social network is being readied for the left’s tumbrels.

The president himself last week “walked back,” as they say, his startling accusation that the company was killing people by hosting supposed misinformation about Covid vaccines. (If walking back were an Olympic sport, the president would be taking home more gold medals this week than the Russian Olympic Committee.)

And you could be forgiven for thinking that the recent declaration that the White House is now working closely with the company to identify further instances of “misinformation” is not an indication of strains between the government and its Silicon Valley friend, but rather an ominous sign of eager public-private collaboration in a more aggressive effort to suppress dissent.

But these may prove to be mere tactical feints in the left’s larger strategic advance against this troublesome tech titan.

Despite the best efforts of the company and increasingly the government, Facebook remains an important conduit for news and views that challenge the prevailing orthodoxies. A Twitter account that tracks the best-performing links on Facebook finds that conservative commentators routinely dominate the top-10 list.

It’s still relatively easy to find dissenting opinions and stories that the bien-pensants of the left denounce as fake, antiscience or harmful.

Facebook can doubtless, without much coercion, be persuaded to do more to rein in this samizdat. But the company faces a larger threat from its allies in Washington. Much more important than the inescapable urge to eliminate thoughtcrime is an objective on the left that might, and perhaps should, attract wider support—even from conservatives. Even as they have embraced the modern cultural agenda of progressivism, there’s a powerful subset of today’s revolutionaries with some more conventional views about economics, competition especially.

If there was any remaining doubt that the Democrats who control Washington have at least the ambition to mount a challenge to the awesome power of the big tech companies, it should surely have been banished by a succession of appointments to key jobs in the Biden administration.

The president has already scared the wits out of Facebook with the installation of Lina Khan as chairman of the Federal Trade Commission. Ms. Khan has been a vocal critic of the company, which has petitioned the FTC (as has Amazon ) seeking her recusal from any cases involving it. Mr. Biden has also appointed Timothy Wu, an academic who has called for the breakup of Facebook, to a senior position in the White House. Last week, the triumvirate was completed with the nomination of Jonathan Kanter to fill the top antitrust position at the Justice Department. Mr. Kanter is to Google what Ms. Khan and Mr. Wu are to Facebook and Amazon. (Mr. Kanter has done legal work for News Corp, which owns the Journal.)

All this suggests not merely a fascinating fissure between the progressives in government and their friends who have done so much to put them there. It points to a wider ideological tension in the progressive movement. Woke companies, especially in the tech sector, have been in the cultural vanguard of the left. But that may not save them from the traditional leftist hostility to big corporations. Thoughtful Republicans with an eye on the populist opportunity are also abandoning their party’s reflexive defense of large corporations.

Much is uncertain. It’s possible that any legal remedies sought by the antitech evangelists in the administration won’t fly—or maybe the risk of rupturing the Silicon Valley-Democratic alliance will force them to stay their hand. But revolutionaries have shown through history that once-useful allies are always expendable in the larger struggle.

(01/15/21) Can right-wing populist sentiment be banished from American life by the brute force of social-media censorship? Images: AP/AFP/Getty Images Composite: Mark Kelly The Wall Street Journal Interactive Edition