These companies, corporate autocracies masquerading as mini-democracies, often portray their moderation decisions as the results of a kind of formulaic due process, as if “don’t incite an insurrectionist mob” had been in the community guidelines all along. But high-stakes calls like these typically come down to gut decisions made under extreme duress. In this case, Mr. Dorsey and Mr. Zuckerberg considered the evidence, consulted their teams, weighed the trade-offs and risks of inaction — including the threat of a worker revolt that could damage their ability to attract top talent — and decided that they’d seen enough…

Mr. Dorsey and Mr. Zuckerberg’s names have never appeared on a ballot. But they have a kind of authority that no elected official on earth can claim. This power appears mostly in subtle and unspoken ways — like the eerily calm, hostage-like video Mr. Trump filmed on Thursday, hours after Twitter and Facebook threatened to delete his accounts. In the video, Mr. Trump conceded that he had lost the election and condemned the Capitol attack, two things he had stubbornly refused to do even as Congress talked of impeaching him a second time and his own Cabinet members discussed invoking the 25th Amendment to remove him from office.

Legal and political concerns certainly pressured the president to adopt a more conciliatory stance. But there was another interpretation of his change of heart: Mr. Trump would rather lose his presidency than his posting privileges.