One power remaining to Boris Johnson, the Prime Minister of the United Kingdom, who has suffered brutal defeats in Parliament and in the courts in recent weeks, is to make Donald Trump laugh. The two men were sitting next to each other at an appearance on Tuesday in New York, where the U.N.’s General Assembly is meeting, and reporters were asking both of them about the biggest blow to Johnson yet: a ruling earlier that day by the U.K. Supreme Court that his advice to the Queen (which she follows as a matter of course) to approve a five-week prorogation, or suspension, of Parliament had been “unlawful.” Johnson began, “We’re full of respect, as I say, for the justices of our Supreme Court.” Before he got that sentence out, Trump broke into a broad grin and practically guffawed. He pointed his thumb at Johnson, in a fond, look-at-this-guy gesture. The idea that the fullness of Johnson included respect for the justices seemed to strike the President as hilarious. “In other words, he’s been very nice to the Court, please. O.K.?” Trump said.

The reason for Trump’s bemusement became clear the next day, when Johnson stood before the House of Commons. He was neither very nice nor even minimally decent. He engaged in a florid display of disrespect not only for the Supreme Court, whose decision he dismissed as “wrong,” but also for Parliament, and for the democratic principles that both institutions represent. He also turned down chances to apologize to the Queen, either for lying to her (something that the Court implied, but did not directly say, he had done) or just for giving her miserably bad advice and dragging her into the whole mess. He accused his opponents of betraying their country and trying to force a “surrender” to the European Union. He called them cowards and seemed to mock the memory of Jo Cox, an M.P. who had campaigned to remain in the E.U. and was assassinated, in 2016, by a man who said, before he shot and stabbed her, “This is for Britain” and “Put Britain first.” Johnson was, in short, unchastened, despite how devastating the Supreme Court’s decision had been. The eleven justices found unanimously that Johnson had acted in order to stop Parliament from carrying out “its constitutional functions” in the crucial weeks leading up to the October 31st deadline for the U.K. to leave the European Union. (The terms of Brexit are still unsettled; there is a lot of work to do.) As a remedy, the Supreme Court declared the whole prorogation null and void. This meant that, technically, Parliament hadn’t ever adjourned; it was as if, the judges wrote, the Queen’s commissioners, who formally delivered the written order shutting down Parliament, had instead “walked in with a blank piece of paper.” Johnson cut his trip to New York short in order to address the M.P.s, who had promptly reassembled and were in a state of uproar. They wanted an apology—“Say sorry!” Jo Swinson, the leader of the Liberal Democrats, demanded—but he delivered insults.

Johnson left behind an American President who has his own troubles. It is tempting to wonder if the time that Johnson spent with Trump contributed to his wild, ill-considered appearance in Parliament. Trump probably didn’t have a sobering effect. And yet it may be more likely that the men share a certain character—mendacious, narcissistic, destructive—than that one influenced the other.

The parallels go beyond style. The fundamental issues that the U.K.’s Supreme Court had to consider echo those that Trump has forced the U.S. Supreme Court to confront. For example, Johnson’s government lawyers had argued that the Court didn’t even have a right to consider whether he had acted properly in the exercise of his executive powers—that the matter wasn't “justiciable.” Trump’s lawyers had made similar arguments at different stages in the various cases regarding his travel ban. And Johnson’s flimsy pretext for a prorogation—that his team needed the five weeks to put together a Queen’s Speech on the “dynamic” domestic policies that it wanted to pursue, which no one believed—recalls the Trump Administration’s claim that the reason it wanted to add a citizenship question to the census was to protect minority voting rights. In both cases, they were effectively arguing that, as long as they come up with some reason for using an executive power, it doesn’t matter if the reason is dubious or entirely fabricated—any excuse is good enough. But reasons do matter: Trump, for example, can withhold military aid from Ukraine for all sorts of reasons; destroying a political opponent doesn’t sound like one of them. In both nations, the Courts pushed back. As Ian Blackford, the parliamentary leader of the Scottish National Party, put it, “The Prime Minister fought the law, but the law won.”

Johnson, in Parliament, clung to the idea that the Supreme Court didn’t have the right to examine what he was doing. “It is absolutely no disrespect to the judiciary to say that the court was wrong,” he said; the Court shouldn’t have meddled in what he called a “political” matter. He further declined to distance himself from a reported comment by Jacob Rees-Mogg, the Tories’ parliamentary leader and an unctuous Brexiteer, that the Supreme Court decision was a “constitutional coup”—ur-Trumpian language. Johnson derided his opponents for “running to the courts to block and delay,” as if there is something unsporting in insisting on the constitutionality of an official act. (The Supreme Court had, in its ruling, responded to cases brought forward in Scotland’s court system by Joanna Cherry, an M.P. with the S.N.P., and in England by Gina Miller, a businesswoman and anti-Brexit campaigner, who was joined by a raft of M.P.s and by the former Tory Prime Minister John Major.) It was all part and parcel, Johnson said, of their “selfishness and political cowardice.”

Even as Johnson’s own delusions were being exposed, he addressed the benches in the House of Commons where the Labour Party members sit: “The members opposite are living in a fantasy world.” Before Parliament was prorogued, it had passed a law requiring Johnson to at least ask the E.U. for an extension if there is no deal on the terms for Brexit by the deadline, in order to prevent the country and its economy from going off a cliff. This is what he called the “surrender act.” In a growing crescendo, a number of M.P.s, several of them women, asked him to refrain from using the language of treachery, invoking Jo Cox and, in some cases, threats that they themselves had received. He did not: surrender, surrender, surrender, he said. Finally, Paula Sherriff, a Labour M.P., rose, almost shaking with anger.

“I genuinely do not seek to stifle robust debate,” she began. But “we stand here, Mr. Speaker, under the shield of our departed friend, with many of us in this place subject to death threats and abuse every single day, and let me tell the Prime Minister that they often quote his words—‘surrender act,’ ‘betrayal,’ ‘traitor’—and I for one am sick of it.” Johnson, she said, should be “absolutely ashamed of himself.”