When I was in college, my roommate, the very sharp Matt Gerke, had taken an undergraduate course in game theory and gotten interested. He went to see the professor, Avinash Dixit, to ask about taking a graduate course in the field in the next semester. Professor Dixit stared intently at Matt as he made his pitch. After Matt was done speaking—without taking his eyes off of him—the professor reached behind his head and pulled a book from the shelf. He opened the book and held it in front of himself with the pages facing Matt. They were filled with abstruse equations and symbols. “Does this look familiar to you?” he asked. “No … no, it doesn’t.” Professor Dixit smiled a thin-lipped smile. “Don’t take game theory,” he said.

My point is that game theory, the study of formal models of rational actors in competition with each other, is hard. Game theory is hard. And so when President Trump, responding to news of the Defense Intelligence Agency’s new assessment about North Korea’s steps towards a nuclear ICBM capable of hitting the United States, says that the North Koreans “will be met with fire and fury like the world has never seen” if they continue to threaten the country, I worry. I would like to think that the President’s comments came after a long-term process of study by Korea analysts, China analysts, nuclear and military strategists, and diplomats throughout the government, who have determined, based on their study of the situation and the personalities, that this sort of threat is the most rational way to decrease the chance of war. It may well be so. But I can’t feel very confident about that. Can you?

Seventy-two years ago today, the United States dropped an atomic bomb on Nagasaki. A few days earlier, President Truman, whose words President Trump has echoed, warned the Japanese to “expect a rain of ruin from the air, the like of which has never been seen on this earth” if they didn’t surrender. The times are different, the situation is different. And we had not yet eaten of the fruit of the tree of nuclear knowledge. But we know that bold threats do not always avoid nuclear conflict.