BEIRUT — Secretary of State Rex Tillerson on Wednesday committed the United States to an indefinite military presence in Syria, citing a range of policy goals that extend far beyond the defeat of the Islamic State as conditions for American troops to go home.

But a crisis unfolding on the Syria-Turkey border that threatens to embroil the U.S. military in a wider regional conflict underscored how hard it will be for the relatively small U.S. presence in Syria to influence the outcome of the conflict there.

Speaking in a major Syria-policy address hosted at Stanford University by the Hoover Institution, Tillerson listed vanquishing al-Qaeda, ousting Iran and securing a peace settlement that excludes President Bashar al-Assad as among the goals of a continued presence in Syria of about 2,000 American troopscurrently deployed in a Kurdish-controlled corner of northeastern Syria.

His comments represented the most comprehensive and ambitious articulation of Washington’s often-contradictory policy in Syria since President Trump took office a year ago, and they underline the extent to which the war against the Islamic State has inevitably also entangled the United States in the region’s other conflicts.

The U.S. troops in northeastern Syria were initially deployed during the Obama presidency to aid local Kurdish forces in the fight against the Islamic State. Their presence now appears to be evolving into a wider regional policy aimed, among its goals, at fulfilling the Trump administration’s promises to get tough on Iran.

Tillerson said the experience of the U.S. withdrawal from Iraq in 2011, which was followed by the rise of the Islamic State and the U.S. military’s return to the region, necessitated an open-ended U.S. presence in Syria to prevent a revival of the Islamic State.

“We cannot repeat the mistake of 2011, where a premature departure from Iraq allowed al-Qaeda in Iraq to survive and eventually become ISIS,” Tillerson said, using an acronym for the Islamic State.

But he also indicated that one of the biggest challenges of the post-Islamic State era is Iran’s enhanced role. With the Islamic State now beaten back into a small pocket of territory along the Iraq-Syria border, the United States has to address the reality that Iran’s support for Assad in Syria has given Tehran a vastly expanded reach, he said.

Source www.washingtonpost.com