A panel of former national security officials and other experts is calling for the White House and lawmakers to "halt the U.S. military withdrawal" from Syria or face potentially dire consequences.
The conclusion, at odds with plans announced late last year by U.S. President Donald Trump, is part of the final consensus report by the Syria Study Group, charged by lawmakers with helping the country craft U.S. strategy going forward.
"The Group believes that the United States is still able to exercise influence over the conflict's trajectory, and that it must do so given the threats the conflict poses to American interests," according to the report submitted to Congress Tuesday. "The United States maintains leverage to shape an outcome in Syria that protects core U.S. national security interests."
The report warns the path forward will not be easy and that it could still be years before Syria ceases to be a haven for both terrorist groups and U.S. adversaries such as Russia and Iran.
"This is a conflict where our two great strategic concerns — international terrorism on the one hand, great power conflict on the other — come together," Michael Singh, co-chair of the Syria Study Group, told lawmakers. "It's not a conflict we can simply contain or ignore."
Singh, a former senior director at the White House for Near East and North African Affairs, said that without reinvigorated and committed leadership from Washington, the threats emanating from Syria are only likely to increase.
"It could yet grow worse," he warned, pointing to a possible new exodus of refugees from Idlib — the last stronghold for some terrorist groups as well as Syrian rebels — and a flashpoint between Russia, Turkey and forces loyal to Syrian President Bashar al-Assad.
In addition, there are concerns about continued escalation in the conflict between Iran and Israel, as well as about simmering tensions between Turkey and Kurdish forces in northeastern Syria, many of which fought against Islamic State as part of the U.S.-led coalition.
IS, despite having lost control of all its territory, also poses an ongoing threat, the group warned.
"The ISIS detainee population is a few prison breaks away from reconstituting the next caliphate," said Dana Stroul, co-chair of the Syria Study Group.
Stroul, a former staff member on the Senate Foreign Relations Committee who previously worked at the Pentagon, warned there are other consequences for a U.S. withdrawal, including an evermore defiant Syrian regime, backed by a further emboldened Russia and Iran.
"Assad, Iran and Russia have faced no meaningful consequences for the use of chemical weapons and barrel bombs, torture, starvation and intentional targeting of civilian infrastructure," she said.
"Iranian boots are not leaving Syria despite U.S. sanctions and Israeli strikes," she added. "Iran is entrenching itself in Syria's economic and social fabric for long-term influence."
Both Singh and Stroul said the U.S. needed to use the tools it already has in place, including a limited number of troops, allied forces on the ground and aid programs, to prevent a further deterioration of the conflict.
"The tools for this strategy are already on the table," she said. "But effective and appropriate resourcing of these tools are needed to give them teeth."
Some lawmakers remained skeptical.
"My worry is that the recommendations you are making to us are just an invitation for the status quo to persist," Democratic Sen. Chris Murphy said.
Stroul insisted, at least for now, the small U.S. military presence in Syria and the persistence of allies on the ground give Washington "a decisive form of leverage, if not right this minute, down the line."
"The only party in this conflict who has a clear vision for how they see it end is Bashar al-Assad," Singh said, noting the only realistic near-term hope for Syria is for Assad to modify his behavior.
"As long as there's a question, for example, as to whether we're really committed to doing this ... that may give him the belief that he can wait us out," Singh added.