TEHRAN, Iran — It took the images of large numbers of dead children lined up in neat rows, snuffed out by a method of warfare that breached Obama’s so-called "red line," for the US administration to seriously consider the prospect of intervening militarily in Syria for the first time since the conflict erupted in spring 2011.

Aside from providing definitive evidence that the regime — and not the rebels he supports — is responsible for the attack, Obama must demonstrate he has exhausted all diplomatic efforts to de-escalate the crisis before he can justifiably go to war. This means talking to Iran.

Fortunately for the United States, the time has never been better to seek Iran’s assistance in helping to stem or even stop the violence tearing Syria apart. Iran’s new President Hassan Rouhani won a landslide majority after campaigning on engaging with the West, defeating isolationist conservatives. This week, he responded quickly to the attack in Syria by condemning the use of chemical weapons, which have killed or injured 100,000 Iranians.

In an interview with the Islamic Republic News Agency, Iran’s new Foreign Minister Mohammad Javad Zarif elaborated on his president’s condemnation.