Russia and the United States have a chance "to appropriately coordinate in Syria" so that refugees can return home, Secretary of State Rex Tillerson said.

Tillerson proposed that Russia and the United States "explore the possibility" of establishing no-fly zones and other "joint mechanisms" to maintain peace in Syria as the Islamic State loses ground. Such cooperation would expand on the military-to-military contacts that have been used to avoid a direct conflict between Russian and American forces operating in the country — but it could be imperiled nonetheless by the fact that Russia and Iran, which have supported Syrian President Bashar Assad, have significant ambitions in a post-ISIS Syria.

"With the liberation of Raqqa now underway, ISIS has been badly wounded, and is could be on the brink of complete defeat in Syria if all parties focus on this objective," Tillerson said in a Wednesday evening statement. "In order to complete the mission, the international community, and especially Russia, must remove obstacles to the defeat of ISIS and help provide stability that prevents ISIS from rising anew from the ashes of their failed and fraudulent caliphate."

Tillerson outlined the U.S. position in advance of a highly anticipated meeting between President Trump and Russian President Vladimir Putin on the sidelines of the impending G-20 Summit in Germany. Trump and Putin are expected to discuss a range of policy disagreements, including Syria and the ongoing crisis in Ukraine.

"The United States and Russia certainly have unresolved differences on a number of issues, but we have the potential to appropriately coordinate in Syria in order to produce stability and serve our mutual security interests," Tillerson said. "The United States is prepared to explore the possibility of establishing with Russia joint mechanisms for ensuring stability, including no-fly zones, on the ground ceasefire observers, and coordinated delivery of humanitarian assistance."

That proposal is redolent of a deal that then-Secretary of State John Kerry attempted to negotiate and implement in the waning months of the Obama administration. As Russia and Assad carried out the siege of Aleppo, a major rebel stronghold, Kerry tried to broker a ceasefire that would produce military cooperation between Russia and the United States — a major concession to the Russians, as the Obama administration attempted to isolate them over the invasion of Ukraine — in exchange for allowing humanitarian aid into Aleppo.

That plan failed as the ceasefire didn't hold, most notably when Russia or Assad forced bombed a United Nations convoy trying to deliver aid to the siege victims. "Russia and the regime owe the world more than an explanation about why they keep hitting hospitals," Kerry said last year. "This is a targeted strategy to terrorize civilians and to kill anybody and everybody who is in the way of their military objectives."

Those objectives could imperil the success of Tillerson's offer, as well. U.S. leaders in both parties believe that Russia and Iran have major long-term objectives in Syria, independent of any desire to defeat ISIS. Those goals, such as Iran's desire to control territory in Syria and Iraq that would amount to a "land-bridge" between Iran and a terrorist group they support in Lebanon, could undermine U.S. interests and endanger Israel.

"The United States believes Russia, as a guarantor of the Assad regime and an early entrant into the Syrian conflict, has a responsibility to ensure that the needs of the Syrian people are met and that no faction in Syria illegitimately re-takes or occupies areas liberated from ISIS' or other terrorist groups' control," Tillerson said, in an apparent acknowledgement of those worries.

Some of Trump's Republican allies might chafe at the proposal, but it's not clear how the United States can prevent Russia and Iran from achieving their objectives without a larger military commitment by the American armed forces.

"I believe that we'll continue to take out ISIS leadership and create havoc for ISIS and al Qaeda in the region; however, you take the longer term risk of empowering the [Iran-backed] Shias and the Russians and the Assad regime to create more havoc for the West," House Intelligence Chairman Devin Nunes told the Washington Examiner in June.

Tillerson, however, hopes that Russia and the United States can cooperate in a way that doesn't compromise American interests. "If our two countries work together to establish stability on the ground, it will lay a foundation for progress on the settlement of Syria's political future," he said.