It’s not clear what time Donald Trump, our restless President, was told of the latest North Korean nuclear test, which took place close to midnight Saturday, Washington time, and was that nation’s largest yet—Kim Jong-un’s first hydrogen bomb, apparently. But it only took until 7:30 A.M. for Trump to make an extremely dangerous and volatile situation worse. He did so, in part, by attacking South Korea, America’s ally and a country at risk in any confrontation—its capital, Seoul, home to ten million people, is close to the border, within range of the North’s artillery—for a supposed lack of toughness. Even at a moment of historic crisis, Trump can’t shake his bully’s instincts: disdain those who you think are weak; home in on and mock the vulnerable; blind yourself to the realities of your own circumstances and character; and pretend that a brawl will make it all better, despite the certainty that it won’t.

The first tweet was relatively straightforward: “North Korea has conducted a major Nuclear Test. Their words and actions continue to be very hostile and dangerous to the United States.....” “Major” is an apt word: tremors of the underground test, including an aftershock suggesting the collapse of whatever cave or chamber it was in, were felt in both South Korea and China, and detected as far away as Argentina. North Korea has falsely bragged about the size of its bombs before, and the stage management of this test—a picture of Kim inspecting a mystery weapon, shown on North Korean television hours before—might have signalled that this, North Korea’s sixth nuclear test, was exaggerated. But the seismic measurements indicate that its power is many times that of North Korea’s previous detonations, and also about a half dozen times more powerful than the bomb that destroyed Hiroshima. But, as Trump’s elongated ellipsis suggested, he wasn’t just going to talk about the facts. He had some blame to dole out.

“North Korea is a rogue nation which has become a great threat and embarrassment to China, which is trying to help but with little success,” he tweeted next. And then: “South Korea is finding, as I have told them, that their talk of appeasement with North Korea will not work, they only understand one thing!”

What is that “one thing”? War, missiles, tweets, Trumpism? “Fire and fury like the world has never seen,” as Trump promised to inflict on North Korea last month if the country acted in a hostile manner? (Trump made that threat at an event at which he was supposed to be talking about the opioid crisis, and it had the effect of distracting attention from that situation; similarly, his latest remarks may take necessary attention away from the aftermath of Hurricane Harvey.) It seems to have escaped Trump that matters with North Korea, never good, have deteriorated during his Presidency. What has changed is not the South’s “appeasement” but his heedless will toward escalation. That the people of Seoul, who have built up their city, and, over the years, their democracy, in the face of the spectre of war, might have their own definition of fortitude is an idea that he doesn’t seem able to grasp. (As the Times noted, Trump’s anger at South Korea appears to be connected to his anger over his so far unsuccessful attempt to rewrite trade deals with that nation—an issue that, one hopes, will not be entangled with the question of triggering a nuclear war.) Instead, last week, Trump said that he thought that Kim had begun to show “respect” for him. That boast was followed by North Korea’s firing of a ballistic missile on a flight path that took it over the Japanese island of Hokkaido. Trump responded by tweeting, “The U.S. has been talking to North Korea, and paying them extortion money, for 25 years. Talking is not the answer!” What, again, is Trump’s answer? China, which quickly condemned the test, could certainly do more, but baiting its officials with talk of their “embarrassment” may not be the best mode of persuasion—unless Trump thinks that he has cowed President Xi Jinping into a state of abject respect for him, too.

“Mr. President, will you attack North Korea?” a reporter asked Trump on Sunday morning, as he was leaving church, a couple of hours after his tweets. He answered, “We’ll see.” By then, his national-security team had mustered, to deal with both Kim and, presumably, Trump. In yet another tweet, a little after noon, Trump said, “I will be meeting General Kelly, General Mattis and other military leaders at the White House to discuss North Korea. Thank you.” It is revealing that Trump still classifies John Kelly, his chief of staff, who, like James Mattis, his Secretary of Defense, is retired from the Marines, as a general and a military leader. And was that “Thank you.” directed at them? There are reasons it should be: within an hour of Trump’s rejection of talk last week, Mattis told reporters that “we’re never out of diplomatic solutions.”

Mattis was also asked, in a separate encounter with reporters last week, why he hadn’t quit working for Trump. “You know, when a President of the United States asks you to do something, I come,” he said. “I don’t care if it’s Republican or Democrat; we all have an obligation to serve. That’s all there is to it.” Mattis added that he had had arguments with Trump, he said, but “this is not a man who’s immune to being persuaded, if he thinks you’ve got an argument. So anyway, press on.” Press on, and hope, meanwhile, that President Trump will not press any buttons.

Perhaps Mattis put that proposition to the test in his meeting with Trump Sunday afternoon. Afterward, Mattis emerged to make a brief statement, in which he said that North Korea should be aware that any threat to America or its allies could be met with a “massive military response.” But he also noted that the United States was not a lone enforcer, and that the United Nations had spoken with a “unified voice” in calling for a denuclearization of the Korean peninsula. He hoped that Kim was listening to all of them, “because we are not looking to the total annihilation of a country, namely North Korea. But as I said we have many options to do so.” President Trump, Mattis said, had “wanted to be briefed on each one of them.”