The new Johns Hopkins SAIS dean, Vali Nasr, is right to worry, in this New York Times op-ed, about the dangers lurking in a post-Assad Syria, which could turn out to experience a civil war like Lebanon or Iraq did–only with scant hope of outside forces (the Syrian army in Lebanon, the U.S. Army in Iraq)  intervening to end the carnage. But he is advocating the height of unrealism when he argues that to prevent the worst, “the United States and its allies must enlist the cooperation of Mr. Assad’s allies — Russia and, especially, Iran — to find a power-sharing arrangement for a post-Assad Syria that all sides can support, however difficult that may be to achieve.”

Iran is the No. 1 backer of the Assad regime. As a Shi’ite state it is closely linked with Assad’s Alawite clan, an offshoot of Shia Islam. But Alawites are only 12 percent or so of the Syrian population. There is scant chance the overwhelmingly Sunni population will stand for the Alawites and their Iranian backers maintaining a significant share of power in a post-Assad state. Nor is this in America’s interest–the biggest upside of the fall of Assad, from our perspective, is that it will deny Iran a foothold in the Levant and hopefully lead to a decrease in support for Hezbollah. The chances of Russia–another backer of the ancient regime–maintaining a significant role in a post-Assad Syria are even more remote.

Nasr’s suggestion is reminiscent of the popular Washington delusion about Iraq, circa 2006, that its problems could somehow be solved by a “regional contact group” that would rope in interested parties from Iran to Saudi Arabia. This overlooked the fact that (a) countries such as Iran and Saudi Arabia had diametrically opposed interests in Iraq; and (b) outside players could not really control a volatile state anyway–that required boots on the ground. Both objections are just as valid in Syria as they were in Iraq.

The way forward in Syria does not lie in trying to perpetuate Iran’s malign influence, which is likely to be employed to keep the civil war going by providing backing for Assad’s security forces. The best bet at this point is to work, along with relatively moderate regional allies such as Turkey, the UAE, the Kurdish Regional Government in Iraq, and Jordan, to bolster the more moderate rebel factions and to try to help them build up security and governance capacity so that they can take over once Assad is gone. This could be aided by setting up safe zones along the border with Turkey and Jordan which the rebels could administer in, one hopes, an inclusive fashion that will send a signal to Alawites, Christians, Kurds and other minorities that their interests will be safeguarded in a post-Assad Syria. Sending international peacekeepers to aid the transition once Assad is gone is also a good idea but unlikely to occur.

Trying to cut a deal with Iran, by contrast, is a bad idea and one with little likelihood of success. If we were to try it, the most likely consequence would be to alienate the U.S. from anti-Assad groups and limit our influence in post-Assad Syria.