Obama understands that the decision he made to step back from air strikes, and to allow the violation of a red line he himself had drawn to go unpunished, will be interrogated mercilessly by historians. But today that decision is a source of deep satisfaction for him.

“I’m very proud of this moment,” he told me. “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, not only with respect to Syria but also with respect to our democracy, was as tough a decision as I’ve made—and I believe ultimately it was the right decision to make.”

This was the moment the president believes he finally broke with what he calls, derisively, the “Washington playbook.”