Why did Donald Trump last week reveal highly classified, potentially life-endangering, intelligence to Russia’s foreign minister? Because he wanted to impress him.

“In his conversations with the Russian officials,” reports Reuters, “Trump appeared to be boasting about his knowledge of the looming threats, telling them he was briefed on ‘great intel every day.’”

It fits a pattern; Trump loves dazzling guests. After his April meeting with Xi Jinping at Mar-a-Lago, he recounted the Chinese president’s supposed shock when Trump told him, over dessert, that the U.S. had just bombed Syria: Xi “paused for 10 seconds and then he asked the interpreter to please say it again.” When two Time reporters followed Trump around the White House last month, Trump told them that Ronald Lauder “went crazy” after being shown “the painting of George Washington above the fireplace.” Then Trump beckoned the reporters to follow him into his private dining room, where “You’ll see something that is amazing.” It turned out to be Trump’s newly installed flat-screen TV.

It’s not exactly a secret that Trump brags. During the campaign, he boasted about the size of his penis. This March, he said he was the reason no NFL team had signed Colin Kaepernick. And he does so in private, too. In his infamous Access Hollywood tape, Trump crowed about his ability to get away with sexual assault, declaring that, “when you’re a star, they let you do it. You can do anything.”

One might hope Trump would realize that Sergei Lavrov is not Billy Bush. In dealing with foreign leaders, presidents are not supposed to brag about the powers of their office. They’re supposed to pursue the national interest. But even in private, Trump appears obsessed with using the presidency to prove how important and successful he is.

It’s a vicious cycle. The more he uses his office to stroke his ego, the more he reveals how unsuited for it he is. The grander he tries to appear, the smaller he looks.