Greg Scoblete casts doubt on the idea that the Russian deal on Syria will encourage Iran to see the U.S. as a more reliable negotiating partner:

Moreover, it’s going to be very difficult for Iran to accept the idea that the Syrian deal shows the Obama administration isn’t seeking Iran’s destruction when the Pentagon talks openly about arming Syria’s opposition even with a chemical weapons deal in place. That sends exactly the opposite message to Iran, who need only look to Libya to understand the consequences of accepting a Western disarmament deal.

Finally, it’s also worth considering what lesson Washington will take away from this: namely, that threats of military force are vital to forging a diplomatic breakthrough (something many Iran analysts have been arguing for a long time). If this becomes the conventional wisdom, it could provoke the administration into another high-wire act, threatening military strikes against Iran and then banking on a last minute diplomatic breakthrough to peaceably bring about a deal.

I hope that Scoblete is wrong about this, but he makes some important points that need to be considered. It is not clear that Russia and Syria were intimidated by the threat of a military attack that Congress was already on track to reject, but the instant consensus in the U.S. seems to be that they were. Iran hawks in the U.S. will presumably conclude from this episode that threatening Iran with attack will yield more results than offering sanctions relief or other concessions. Since offering sanctions relief is a much more productive way to reach an agreement on the nuclear issue and gives Iran an incentive to accept a deal, that would be a serious mistake, but it would be the same one that the U.S. has been making in its Iran policy for years. Another difficulty is that Iran doesn’t view its nuclear program, which it is legally permitted to have, as something comparable to Syria’s chemical weapons arsenal. That means that Iran will need to be offered more to make concessions on the nuclear issue than the U.S. is willing to offer Syria, and it won’t be willing to agree to maximalist demands on enrichment. Assuming the Russian deal works, it should create better conditions for negotiations with Iran, but for that to happen the U.S. can’t approach those negotiations with the assumption that Iran can be made to capitulate.

Iran can’t help but notice that states that agree to disarmament don’t buy themselves security from attack or foreign support for their domestic opponents. The fact that the U.S. continues to threaten Iran with attack in the name of “prevention” must mean more to Tehran than the U.S. decision not to attack Syria. The recent conciliatory gestures from Rouhani are an encouraging sign that tensions between the U.S. and Iran can be reduced, but there has to be some effort on Washington’s part to reciprocate or the chance will quickly be lost. Avoiding an attack on Syria should make diplomacy with Iran more productive, but whether it produces an agreement will depend on the willingness of the U.S. to make the concessions necessary to reach one.