What this means, in sum, is that the defense of the capital and the critical points of the regime enclave is now almost entirely in the hands of the Iranians and their militias — who are also under severe pressure in Iraq, where even with the aid of the US Air Force they are hard pressed to roll back the Islamic State. Their ability to expand much more beyond the enclave’s perimeter is dubious. 

All of this raises an acute question about American foreign policy. Is this really the right moment to provide Iran with a massive cash infusion? The Iranian system is under strain. Wouldn’t it make more sense for the United States to exacerbate the strain rather than relieve it?

Instead, the Obama administration is helping sustain the Iranian regional project.