Second, Iran is still a powerbroker in the Caspian oil trade; its position on the Caspian Sea, which is estimated to hold more than 10 billion tons of oil reserves, makes it an important and influential partner for Russia. Tehran has been extensively involved in coordinating transnational oil and gas deals, arranging transportation of exports with a number of regional states. Russia is in a position to use its good relations with Iran to challenge Washington's efforts to create new pipelines and foreign direct investment in the Caspian region. Iran has already proven an effective regional ally for Russia--in addition to cooperating on energy deals, Tehran has pointedly refrained from criticizing Moscow's Chechnya policy and has held strategic meetings with Moscow on the Taliban.
Finally, Russian nuclear cooperation with Iran provides the Kremlin with leverage over the United States. Moscow remains guarded against Western advances into its "near abroad," and has fought to keep neighboring states from being brought into the NATO fold. By dangling the Iranian nuclear issue in front of the United States, Moscow may believe it has a means to maintain regional dominance. Russian leaders have already extracted concessions from Washington, as the United States recently altered plans for missile defense in Poland and the Czech Republic. Yielding on the Iran issue would strip Moscow of the ability to coerce the United States and damage its own ability to reassert local influence.
If the United States seeks true Russian support, it must find a way to compensate Moscow for the losses it will incur by forsaking Iran. Washington will continue negotiating with both countries, and it remains possible that the parties may agree on a compromise that would give Iran a reprieve from further sanctions. But the Obama administration, wary of Tehran's promises, is likely to continue laying the groundwork for future penalties in the case of Iranian backtracking. As it does so, it is worth remembering that Russia has already supported multiple rounds of UN Security Council sanctions, but only those that have not imperiled its own interests. Efforts to court Russia that do not account for the country's long and profitable investment in the Iranian nuclear program rely on misplaced optimism, and will likely end in diplomatic disappointment.
Seth Robinson, a former staff member of the House Committee on Foreign Affairs, is a PhD candidate in International Relations at Georgetown University.