As the Trump administration winds down the fight against the Islamic State in Iraq and Syria, Iran is gearing up to expand its territorial gains in the region, stoking concern among U.S. allies and partners.
Iran is establishing military bases in recently seized territory in southern Syria with the support of President Bashar al-Assad and has made clear its desire to seize the country's oil-rich Deir al-Zour province.
A ceasefire deal recently brokered between the United States, Russia, and Jordan to establish a de-escalation zone in the southwestern region bordering Israel and Jordan will do little to constrain Iran's ambitions.
Israeli Prime Minister Benjamin Netanyahu has complained the truce, intended to secure liberated territories from the Assad regime, lacks an adequate enforcement mechanism to keep Iran and Hezbollah from positioning forces in the buffer zone. Russian Foreign Minister Sergei Lavrov said a week after the deal's signing the Kremlin would not force Iran to exit Syria, despite statements to the contrary by the Trump administration.
Iran has been racing against U.S.-backed forces to carve out a land corridor connecting Tehran to the Mediterranean. The route would enable Tehran to hold communication lines and more easily move its forces, including the Iranian Revolutionary Guard, Hezbollah, and other Shia militias in the region.
Lacking a coherent strategy proposal from President Donald Trump post-ISIS, a coalition of former senior-level U.S. diplomatic and military officials recently released a series of recommendations for the administration to combat Iran's spread in Syria.
"The United States must impose real obstacles to Tehran's pursuit of total victory by the Assad regime in Syria," said the report by the Jewish Institute for National Security of America. "Any further strategic gains threaten to entrench Tehran as the arbiter of postwar Syria and consolidate its control of a 'land bridge' connecting Iran directly to Lebanon and Hezbollah."
The JINSA task force recommended Trump lay out a decisive strategy in Syria and make clear the United States will maintain troops on the ground and in the air, even after the inevitable fall of ISIS. The administration must make clear the troops will provide security for reconstruction and prevent both the reemergence of the jihadist group and Assad recapturing the entire country.
The Pentagon must also continue to develop the capabilities of those living in areas liberated by U.S.-backed troops to help local forces, primarily the Syrian Democratic Forces, hold strategic territory.
Third, the U.S. must coordinate with regional allies to prevent Iranian weapons proliferation through Syria. The task force recommended Trump do this by escalating maritime monitoring and efforts to interdict shipments from Iran to Syria.
Retired Air Force Gen. Charles Wald, who co-chairs the task force, said the success or failure of Iran in Syria is dependent upon a U.S. strategy.
"We've got to show leadership, I don't care if people say we're too involved, we don't have a choice," Wald to the Washington Free Beacon. "The world is what it is and we've got to be involved and we've got to lead the solution."
Daveed Gartenstein-Ross, a senior fellow at the Foundation for the Defense of Democracies, said while the lack of a U.S. strategy certainly helped Iran gain power, it's unlikely the Trump administration will be able to prevent Tehran from expanding its influence in the near-to-medium term.
"Iran has basically created its own foreign legion," he said. "You've had a variety of Shia militias from other countries, including from Afghanistan, Pakistan, Bahrain, and elsewhere, come to the Syrian-Iraq theatre to aid in the fighting, not just against ISIS, but also to aid the fight for Assad. That's something which gives it the ability to project power significantly."
That's not to say Trump should abandon Syria entirely. Gartenstein-Ross said the United States needs a clear strategy in the region to succeed in the long run.