Indeed, the images of collateral damages and the unintended consequences of U.S. military action in Syria would have reignited war fatigue in the U.S. And with war-bashing on the rise, the U.S. administration would have been obliged to give a higher priority to extricating itself from Syria than to tackling Iran’s nuclear designs.

Now there’s no luck for the mullahs. The likelihood of a U.S. military involvement in Syria has faded away. As a matter of fact, it is Iran that could eventually end up in the unenviable position of fighting on two fronts, namely at home against a U.S. attack and in the Syrian battlefield against hostile, Sunni jihadists eager to inflict damage to the Shiites in power in Tehran. The situation is all the more worrisome for Iran as the Sunni jihadists have been tightening their grip on the Syrian insurgency.

Meanwhile, Iran is investing resources and efforts in an effort to protect Assad’s regime, its only ally in the region. No wonder a U.S. officer has referred to Syria as being “Iran’s Vietnam.”

Thus, by staying away from the Syrian theater of operations while Shiite Iran frets about the mounting influence of Sunni jihadists in its neighborhood, this administration has added pressure on Iran’s leadership to try to reach a diplomatic settlement of the standoff over its nuclear plans. Hence Rouhani’s conciliatory rhetoric.