Story highlights President Barack Obama says there's not much that could have been done differently in Syria

His administration made the best decisions based on information available at the time, he says

Washington (CNN) Syria's prolonged and bloody civil war "haunts" President Barack Obama, he told an interviewer this month, though he isn't naming any specific policy change he believes could have stemmed the suffering there.

Speaking with presidential historian Doris Kearns Goodwin for Vanity Fair, Obama said the grim situation in Syria "haunts me constantly."

"I would say of all the things that have happened during the course of my presidency, the knowledge that you have hundreds of thousands of people who have been killed, millions who have been displaced, (makes me) ask myself what might I have done differently along the course of the last five, six years," he said.

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Obama's efforts to ease the humanitarian crisis in Syria have largely fallen short since an uprising against President Bashar al-Assad turned violent five years ago. The latest attempt with Russia to broker peace in Syria is unraveling amid mutual recriminations.

"The conventional arguments about what could have been done are wrong," he said. "But I do ask myself, 'Was there something that we hadn't thought of? Was there some move that is beyond what was being presented to me that maybe a Churchill could have seen, or an Eisenhower might have figured out?'"

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