So it’s official: If he gets to dish it out, he has to take it too. At least for now.

A federal appeals court ruled Tuesday that President Trump cannot block his critics on Twitter. The decision upholds a 2018 district court ruling that said the president had tried to do an end run around the First Amendment in blocking critics, noting that public officials could not turn off people “from an otherwise open online dialogue because they expressed views with which the official disagrees.”

Karma is not just analog.

The latest ruling will be on the top of the agenda this week at a White House social-media conference (Twitter and Facebook have not been invited, making the gathering pointless). The event will be packed with conservatives who think, like Mr. Trump, that they are being discriminated against by the social media giants — with no substantial evidence to support this claim.

In fact, those who complain most loudly about being sidelined on social media never seem to stop their noisy tweeting. Mr. Trump is the perfect example: He’s a 24/7 gusher of bilious ALL CAPS tweeting that never runs dry. And it never will: The court ruling Tuesday cements the marriage of Mr. Trump and Twitter in perpetuity.

Twitter is now less likely than ever to throw Mr. Trump — the most egregious breaker of its rules, its troll extraordinaire — off its platform. Still, it’s worth thinking about what would happen if Mr. Trump’s prime vehicle for spewing, and for governing, was removed from his PR toolbox.