By Andrew J. Tabler – New York Times – September 5, 2013 – Achieving U.S. objectives in Syria would help pressure Tehran into making hard choices regarding both the Assad regime and the Iranian nuclear program.

While Washington debates how the United States should respond to its intelligence reports of Syrian President Bashar al-Assad’s use of chemical weapons on civilians, the war in Syria in one shape or form will go on for years.

Syria’s partition into three general parts not only threatens the post-World War I boundaries in the Middle East, but U.S.-designated terrorist organizations are now ascendant in each part, with Al Qaeda affiliates active among the Sunni opposition and Hezbollah (along with other Shia fighters from elsewhere in the region) playing an increasing role in the Assad regime’s attempt to consolidate its lines of control.

Advising and financing this collective Shia effort is the Islamic Republic of Iran, Syria’s lone ally in the region. At first glance, the festering Syria crisis seems bad news for diplomatic efforts to keep Iran from developing nuclear capabilities. In actuality, however, achieving U.S. objectives in the Syria crisis is an opportunity to pressure Iran into making hard choices not only in Syria, but regarding its nuclear program as well. More U.S. involvement to achieve its objectives in Syria will inevitably run counter to Tehran’s interests, be it to punish the Assad regime for chemical weapons use or to show support for the Syrian opposition in changing Assad’s calculus and forcing him to “step aside” at the negotiating table or on the battlefield.

Many in U.S. policymaking circles have viewed containing swelling Iranian influence in Syria and preventing Iran from going nuclear as two distinct policy discussions, as the Obama Administration only has so much “bandwidth” to deal with Middle East threats. But the recent deepening of cooperation between Tehran, Hezbollah and the Assad regime, combined with their public acknowledgement of these activities, indicates that they themselves see these activities as furthering the efficacy of the “resistance axis.”

Like every alliance, its members will only make hard policy choices if the costs of its current policies far outweigh the benefits. U.S. strikes on the Assad regime, if properly calibrated as part of an overall plan to degrade the regime, would force Tehran to become more involved in Syria in order to rescue its stalwart ally. This would be costly for Iran financially, militarily and politically. Those costs would make the Iranian regime and its people reassess aspirations to go nuclear.

Andrew J. Tabler is a senior fellow at The Washington Institute and author of “In the Lion’s Den: An Eyewitness Account of Washington’s Battle with Syria.”