WASHINGTON -- Despite Americans’ exhaustion with 11 years of foreign conflict, the victor in Tuesday’s presidential race may find it all but impossible to keep the United States from becoming more deeply entangled in the unfolding calamity of Syria’s sectarian civil war.

Pressure for Washington to play a greater role comes from a variety of factors: soaring casualty tolls, hundreds of thousands of refugees flooding into neighboring countries, wholesale destruction of Syria’s infrastructure, the growing presence of al Qaida-linked fighters, fears that violence will spill over into adjacent nations, and the danger that the Assad regime will collapse, leaving Syria’s chemical weapons open to theft.

“The longer this continues, the more sectarian violence is going to take place,” warned F. Stephen Larrabee, an analyst with the RAND Corp., a policy institute. “Sooner or later, the U.S. will arrive at a tipping point where it will have to decide if it will watch from the sidelines as the situation deteriorates or has to take some sort of action.”

Moreover, experts said, having committed themselves to Syrian President Bashar Assad’s ouster, President Barack Obama and Republican hopeful Mitt Romney would have to do more to make certain that goal is achieved. Otherwise, they risk appearing weak and feckless, leaving the U.S. little leverage to shape a post-Assad regime and less influence in the oil-rich region. Such an outcome also could embolden al Qaida and allied groups.

“Our Arab allies have shown some willingness and sensitivity toward the U.S. administration’s reluctance to get involved because of the election,” said Randa Slim of the Middle East Institute, a Washington-based research center. “But after the election, we will see the Gulf (Arab) allies increase pressure on the U.S. to do more. I think we will see the same from the Turks.”

Obama and Romney both have ruled out U.S. military intervention. So the next president will have limited options to contain the mayhem. Those could include more robust efforts to force feuding opposition leaders to agree on the makeup of an alternative government and to identify moderate rebels to whom to channel heavy weapons. The U.S. and Turkey also could deploy anti-aircraft batteries along Turkey’s side of the border to protect civilians and rebels across a swath of northern Syria in a “safe zone” that wouldn’t require U.N. approval, experts said.

Such a zone “is going to change the balance of power. The only way Assad can project power in northern Syria today is by bombing with airplanes and helicopters,” said Joshua Landis, a Syria expert at the University of Oklahoma. “If you take that out . . . then you are getting closer to a . . . situation where the rebels can set up camp and welcome (Syrian army) defectors in a safe environment. They could train and recruit.”

Such options also could end up sucking the U.S. even deeper into the maelstrom pitting rebels mostly from Syria’s Sunni Muslim majority – backed by Saudi Arabia, Qatar, Turkey and Islamists from across the region – against regime forces led by Assad’s Alawite minority, a Shiite Muslim offshoot, backed by Iran’s Shiite rulers and Hezbollah, the Shiite movement that dominates Lebanon’s government. The Shiite-led government of Iraq might also side with the Assad allies.