Trump’s foreign policy has been full of twists and turns, but it has also followed a clear narrative arc. The 10-day period from June 20—when Trump reversed himself on Iran strikes—to the DMZ visit was among the most significant of his presidency, as he was forced to come to terms with the consequences and contradictions of his own decisions. Over the course of three decades, Trump has carefully nurtured two images of himself—as a dealmaker, and as a militarist. Bolton did all he could to encourage the latter. But even from faraway Ulaanbaatar this past weekend, it was clear that, when made to choose, Trump would opt for the former.

To understand where we are and where we are going, we must first understand where we have been. Trump became president with a set of deeply rooted visceral instincts about the world—hostility to alliances, skepticism of free trade, and support for authoritarian strongmen—but little idea about how to convert these beliefs into policy. He had few advisers qualified for high office who believed what he believed. He was insecure. And so he turned to a number of highly experienced businessmen and former military officers to fill key national-security and foreign-policy positions—John Kelly, James Mattis, H. R. McMaster, Gary Cohn, and Rex Tillerson. These men saw their role as constraining the president, not empowering him. They measured their success by what they prevented from happening, rather than by what they made happen. In the Trump epoch, this was the age of constraint.

The president did not always listen to the “axis of adults.” In fact, he took pleasure in defying them on occasion, but he usually returned to the fold under pressure. While delivering a speech at the new NATO headquarters in May 2017, Trump raised doubts about his commitment to the alliance when he took out a sentence endorsing Article 5, the mutual-defense clause of the NATO charter. After the ensuing uproar, he was persuaded to state his support for Article 5 at a press conference with the Romanian president and in a subsequent speech in Poland. Under the leadership of the axis of adults, the administration produced strategic documents reflecting the views of the establishment.

The president grew weary of the adult supervision and he gradually realized that he was the president. He could order his Cabinet members to do what he wished, even if they all objected. We can identify precisely when the age of constraint reached its peak and when it ended. The peak came on July 17, 2017, when the president sat in an interagency meeting to discuss the Iran nuclear deal—specifically the question of whether to recertify Iran’s compliance, an assessment that the United States was required to make every six months. Trump’s team presented him with three options, none of which involved leaving the deal. Trump was furious—he approved a recertification but promised that it would be the last one. By the next deadline, he wanted the option to leave. Bolton immediately began auditioning for the job as Trump’s top security adviser, writing an article in National Review that laid out a plan to leave the Iran deal.