This is not entirely unexpected, but nevertheless, represents a clean break with the Obama administration and, indeed, American history.

Secretary of State Rex Tillerson told UN chief  Antonio Guterres during a private State Department meeting last week that it was up to Russia to decide the fate of President Bashar Assad in post civil war Syria. By washing the US hands of Assad's fate, Tillerson is sending a clear signal that the US will not concern itself with the shape of a post war government and society in Syria.

Foreign Policy:

Tillerson’s assurances to Guterres signaled the Trump administration’s increasing willingness to let Russia take the driver’s seat in Syria, throwing geopolitics to the wayside to focus on defeating ISIS.

He also signaled that U.S. military action against Assad’s forces in recent months is intended to achieve only limited tactical goals–deterring future chemical weapons attacks and protecting U.S. backed-forces fighting the Islamic State in Syria–not weakening the Assad government or strengthening the opposition’s negotiating leverage.

Tillerson’s position reflects a recognition that Syria’s government, backed by Russia and Iran, is emerging as the likely political victor in the country’s six year long civil war. It also marks a further retreat from the 2012 U.N.-brokered Geneva Communique — signed by Russia, the United States, and other key powers — which called for the establishment of a transitional government with members of the regime and the opposition. The Geneva pact, according to the Obama administration and other Western allies, was to result in Assad’s departure from power. (Though the Obama administration softened its own demand that Assad step down during its final year in power).

A State Department official declined to comment on Tillerson’s private discussion with Guterres, but insisted that the U.S. remains “committed to the Geneva process” and supports a “credible political process that can resolve the question of Syria’s future. Ultimately, this process, in our view, will lead to a resolution of Assad’s status.”

“The Syrian people should determine their country’s political future through a political process,” the official added.

Given the post war mess left in Iraq and Libya, Trump's policy goals have the benefit of keeping America's distance from what promises to be a less than peaceful, chaotic post war atmosphere in Syria.

But the policy also carries a geopolitical cost; it empowers and gives influence to Russia in the Middle East after decades of US policies that sought to prevent that eventuality.

What Putin will do with this influence isn't much of a mystery. As the rest of the Middle East backs "the strong horse" in the region, Russia will seek to establish a military presence where they've never had one before. Putin will have new clients for Russian arms, as well as states willing to back his foreign policy. 

The US no longer needs Middle Eastern oil to survive. We have become net exporters of fossil fuels and possess more oil reserves in our shale and beneath oceans off our coast than Saudi Arabia. Europe may have to take a more active role in the region due to their dependence on Russian natural gas and Middle Eastern oil.

The US retreat from Syria and the Middle East was inevitable once our need for the oil disappeared. And Europe, once dependent on the US Navy to keep the oil shipping lanes open, will eventually have to fend for themselves.