The decision to escalate is not his alone. As former CIA Director Michael Hayden said Monday on CNN, there is a strong likelihood that Assad and his patrons in Tehran will retaliate: “We want it to be one and done—the president’s made that very clear: Very limited strikes, very limited objectives—deterring, degrading the potential use of chemical weapons. He’s doing it, our president, to show resolve . . . . But guess what, Assad and his Iranian and Hezbollah allies are going to want to show resolve, too. They’re not going to want to give the United States a free ride for this kind of action.”

The Iranians, Mr. Hayden says, will be “engineering some kind of response.” What will Obama do then?

Even Syrians who might benefit from U.S. military intervention are apprehensive about the limited strikes telegraphed by the White House. “A light strike would be worse than doing nothing,” Abdel Jabbar Akaidi, head of the Free Syrian Army in Aleppo province, told Syria Deeply, a blog about the conflict, this week. “If it’s not the death blow, this game helps the regime even more. The Syrian people will only suffer more death and devastation when the regime retaliates.”…

But a successful intervention requires a commander in chief committed to changing the war’s momentum and changing the regime in Damascus. The White House has eschewed both. The only thing worse than not intervening in Syria would be a failed intervention—an outcome that will make future American interventions, by this president or another, in Syria or elsewhere, even more difficult.