Washington — At the Hanoi summit, perhaps following a champagne toast officially welcoming North Korea to the nuclear club, I imagine President Trump and Kim Jong Un sitting down to watch the Michael Cohen hearing. Not far into the Republican questioning, Kim might have said something like: “I thought I knew toadying, but I’ve never seen anything like this. Don, what is your secret?”

The House of Representatives has always been the shallower end of the legislative pool. But the performance of Republicans at the Cohen hearing was in a class of its own. Their game plan seemed to consist of shouting, vilification and shouted vilification. Most of them apparently got their degrees from the Roy Cohn School of Law.

But Chihuahuas are not intimidating, even when they travel in packs. What passed for a cutting Republican taunt? “Liar. Liar. Pants on Fire!” Honestly, has the ban on child labor been lifted for House staffers? At some point, kissing up involves moral corruption. And Republicans passed that milestone some time ago. Many in Trump’s army of enablers have lost the ability to distinguish political realism from moral surrender. Now they are left to impugn the reputations of the president’s accusers, as though the whole Republican Party had signed on as part of Trump’s legal team. How did Republicans do? Michael Cohen started the hearing with an absolutely awful reputation and still came across looking more trustworthy than his accusers.

Yet the alternatives to this strategy for Republicans are not obvious. Normally, defending a sitting president would involve witnessing to his character. Something along the lines of: “No, Trump has too much integrity to direct Roger Stone to deal with WikiLeaks.” Or: “That isn’t possible. Trump is too good a man to pay hush money to a porn star.” Or: “It is inconceivable that Trump would have had foreknowledge of a meeting at Trump Tower with shady Russians to get dirt on Hillary Clinton. His conscience wouldn’t allow him to go so low.”

Any of these lines spoken aloud at the Cohen hearing would have gotten peals of laughter. Of course Trump is capable of all these disreputable things. The real question is: Was he foolish enough to do them and get caught? So Republicans are staking the future and reputation of their party on the intelligence, or at least cunning, of Donald Trump.

Most of our politics now consists of seeing the same horror from new angles. America has a president who respects no rule of morality, tradition or law that conflicts with his own immediate self-expression or gratification. His only self-limitation, apparently, is plausible deniability — a moral framework that seems to be based on old episodes of “The Sopranos.” This is narcissism that has slipped its leash, roaming wherever it wishes across the wide world, and in our heads.

Years ago, I posed the question: What happens when a narcissist who thinks he is at the center of the universe is actually placed at the center of the universe? We are seeing what happens. The whole apparatus of a political party — including its legislative and religious wings — is now dedicated to the defense of one man’s feral will.

It is worth remembering that things weren’t always this way. Ronald Reagan sought to create a coalition of ideas — the fusion of economic, moral and defense conservativism. Barack Obama won office by turning out a broad coalition of interests.

For Trump — his mind uncluttered by creed or conviction — it can only be a coalition of the loyal. He insists on it. Loyalty to his person is his main — perhaps exclusive — measure of support. Some Americans may be drawn toward Trump’s views on immigration or on trade. But it is absurd to think that Trump, in most cases, holds their loyalty because of immigration or trade policy. His persona is ultimately his appeal. He generally talks not to persuade or inspire but to incite or demean. Man and message are one.

But Republicans are beginning to learn the lesson that Trump’s narcissism is not completely unbound. It could run into Robert Mueller and the rule of law. It could run into the waiting arms of the Southern District of New York. It already has run into the oversight of a Democratic House. And this demonstrates why a vote for House Democrats in the 2018 midterm was (for some of us) a difficult necessity.

— Michael Gerson is a columnist for Washington Post Writers Group.