“I feel like I’m back in seventh grade here, where we have juvenile name-calling,” Representative Mike Quigley , a Democrat, marveled to CNN . “We’re talking about protecting the rule of law, and the best the president can do is start calling people names.”

Trolling the libs with serial outrages — just for, one might say, schiffs and giggles — is a source of endless delight for Mr. Trump. It is also central to his survival strategy: The president burnishes the swaggering, politically incorrect persona that thrills his base, even as he siphons attention away from the substance of the real outrages that his administration is perpetrating on a near-daily basis. Who has time to focus on the finer points of trade policy or prescription drug costs or the continuing assault on democratic institutions when the leader of the free world is tweeting bathroom humor?

This is how Mr. Trump rolls. And if you think he has been over-the-top while his Republican enablers have controlled all of Congress, just wait until the Democrats take over the House in January. This president has repeatedly made clear that he considers himself above the law and accountable to no one. He is unlikely to greet Democratic efforts at oversight with any sort of restraint. Expect the nicknames to get nastier and the attacks more gratuitous. Mr. Trump thrives down in the mud and is eager to drag his opposition down with him.

Over the past two years, there has been much talk about the risk of the public becoming exhausted by Mr. Trump’s constant outrages — of allowing him to normalize bad, dangerous behavior. That remains a risk, but only if we continue to let his potty mouth consume so much public attention.

Mr. Trump’s critics should continue fighting fiercely against his attempts — on Twitter and off — to undermine the rule of law, to rig the system in favor of himself and his cronies and to take down not only the Constitution but also quite possibly, if he gets the chance, the Ptolemaic model, Newton’s Law, and maybe even the Pythagorean theorem in order to establish himself as the sole arbiter of truth.