The consequences of American non-intervention in Syria have, in some ways, been as bad as the consequences of American intervention in Iraq, though fewer American lives and dollars have been expended. Yet the realist in Obama has no regrets. Goldberg does future historians a valuable service by setting out in detail the president’s reasoning.

The president dragged his feet on Syria for three reasons. First, having been elected partly on the strength of his opposition to the Iraq War, he was and remains in principle reluctant to deploy U.S. troops (though not U.S. drones). In 2009, he felt the Pentagon had “jammed” him into approving a troop surge in Afghanistan; four years later, he felt he was being jammed again. Second, he misread the Arab Spring, initially equating protesters in Tunisia and Tahrir Square with Rosa Parks and the “patriots of Boston.”

Third, Obama regretted succumbing to pressure from his own advisers as well as from European allies to intervene in Libya in 2011. When similar pressures were brought to bear on him over the red line he himself had drawn regarding the use of chemical weapons in Syria, Obama revolted. On August 30, 2013—after consulting only Denis McDonough, his chief of staff—he decided to call off planned air strikes against the Syrian government, telling McDonough of his “long-standing resentment: He was tired of watching Washington unthinkingly drift toward war in Muslim countries.”

The president’s rationalizations of his U-turn need not detain us (“Assad would place civilians as ‘human shields’ around obvious targets … U.S. missiles would not be fired at chemical-weapons depots, for fear of sending plumes of poison into the air,” and so forth). The point is that if those arguments had been any good, there would have been no need to circumvent his own cabinet and advisers.

Susan Rice was “shocked.” When he found out that evening, Kerry told a friend: “I just got fucked over.” Even Vice President Joe Biden was on the other side of the argument (“big nations don’t bluff”). The usually loyal Gideon Rose, the editor of Foreign Affairs, thought it was a mistake. So did the crown prince of Abu Dhabi, Mohammed bin Zayed al-Nahyan. So did the king of Jordan. And so, of course, did Hillary Clinton.

When she later made public her criticism of Obama’s handling of Syria, Obama became “rip-shit angry,” according to a senior adviser. It was at this time that the White House went demotic with the facile slogan: “Don’t do stupid shit.” According to Ben Rhodes, Obama’s deputy national-security adviser for strategic communication, “the questions we were asking in the White House were ‘Who exactly is in the stupid-shit caucus? Who is pro–stupid shit?’”

This, then, was The Moment: Obama’s decision not to carry out his threat against Bashar al-Assad was, we are told, the defining moment of his presidency. “I’m very proud of this moment,” he tells Goldberg. “The overwhelming weight of conventional wisdom and the machinery of our national-security apparatus had gone fairly far. The perception was that my credibility was at stake, that America’s credibility was at stake. And so for me to press the pause button at that moment, I knew, would cost me politically. And the fact that I was able to pull back from the immediate pressures and think through in my own mind what was in America’s interest … was as tough a decision as I’ve made.”