There’s been some speculation in the press this week about what a possible thaw in US-Iranian diplomatic relations (the product, no doubt, of an extensive public relations campaign) might mean for several big-picture issues, such as Iran’s nuclear program and the threat of an American strike, the territorial and strategic balance of power in the Persian Gulf, the Arab-Israeli conflict, and so on.

Syria is part of the discussion but it’s not clear what Iran can deliver on this front, assuming that the negotiations on the larger and more complex issues develop productively. Last week, I argued at a teach-in we held at Brown that if the Obama administration is serious about a political solution to the Syrian crisis (or a “political outcome,” as my friend Nadim Shehadi puts it), then the US should be talking to the Iranians, not the Russians. Unlike Moscow, Tehran has an enormous strategic, financial, and military investment in its alliance with Bashar al-Assad, and so has more to lose from the current state of affairs.

Iran exerts considerable leverage over its client, but having leverage means little without a workable political settlement in view. What can Iran actually deliver? A couple weeks ago, we had a debate in the comment section about what a Syrian Ta’if Accord might look like, once the principal combatants agreed to lay down their arms. Very few readers could see their way to such an agreement in the near term, citing geopolitical factors as the main obstacle.

But if the geopolitical environment is looking more amenable to a regional agreement over Syria’s fate — what with Iranian smoke signals and White House pen pal letters — it’s worth asking the question again: What kind of agreement by outside powers can be imposed effectively in Syria, in the way that Ta’if (for all its warts) managed to end Lebanon’s Civil War and has kept the peace for nearly a quarter century?

Steve Walt believes that “the most one could hope for is an agreement that imposed a cease-fire, acknowledged the de facto partition of Syrian territory into government and opposition zones, began negotiations on some sort of power-sharing arrangement, and maybe got outside powers to reduce their support for their various clients.” My regime contacts’ views on what a potential compromise should involve envision a more ambitious process.

If we take Walt’s more limited position as a base line, could Iran help broker such an agreement? Would they commit troops to enforcing a ceasefire, or lend support to a UNIFIL-type force to do the job? Do they have the leverage to force Assad to step down and sponsor a new power-sharing arrangement in Syria? At this point, it may not even be sensical to speak about a “political solution” in Syria without some form of military involvement to enforce it, just as Syria enforced the Ta’if Agreement in Lebanon.

And, of course, assuming one can even separate the Syrian file from all the larger issues involved, how to square the Resistance/Hizbullah circle? Rouhani is in no position to sacrifice a major strategic asset in the service of better relations with the United States. Unless, of course, the Arab-Israeli conflict is solved in the process.

Surely that’s what President Obama’s plan was all along.