At the White House, spokesman Josh Earnest said the president condemned any use of chemical weapons in Syria. Earnest said the United States had no independent evidence of the use of chemical weapons but that it urged Syria to allow the United Nations investigative team to gather evidence.
“The use of chemical weapons is something that the United States finds totally deplorable and completely unacceptable,” he said. “Those who are responsible for the use of chemical weapons, if it’s determined that that’s what happened, will be held accountable.”
Earnest said Obama and his aides were reviewing the situation and that he had no policy changes to announce. He did say the president “wouldn’t rule out additional assistance.” Already, the United States is providing the largest amount of humanitarian aid to Syria.
Tamara Cofman Wittes, the director of the centrist Brookings Institution’s Saban Center for Middle East Policy in Washington, said that even evidence of chemical weapons use in Syria might not be enough to prompt U.S. intervention. She sees an “erosion” of Obama’s red line.
Since the first U.S. warning about chemical weapons, the Syrian battlefield has changed. Jihadists have taken a lead role in the rebel movement, while the regime got a boost from Hezbollah militants and from Iranian and Russian arms.
As the war has ground on, U.S. officials have become increasingly vague about what would force an intervention.
“I’m not sure the chemical weapons issue is as much a determinant of policy as it was,” Cofman Wittes said. Until last year, she was a chief coordinator of the administration’s Arab Spring response from the State Department and was the deputy assistant secretary for near eastern affairs.
She noted that Obama’s remarks in a TV interview with Charlie Rose in June suggested that the administration’s red lines had faded. In that appearance, Obama made it clear that he’d proceed with caution in response to any chemical-weapons claims.
“Have we mapped out all of the chemical weapons facilities inside of Syria to make sure that we don’t drop a bomb on a chemical weapons facility that ends up then dispersing chemical weapons and killing civilians, which is exactly what we’re trying to prevent?” Obama said. “Unless you’ve been involved in those conversations, then it’s kind of hard for you to understand the complexity of the situation and how we have to not rush into one more war in the Middle East.”
Cofman Wittes said that a confirmed chemical weapons attack could help the United States nudge Russia, which has strongly backed Assad over international objections.
“If there’s evidence of regime use of chemical weapons,” she said, “it certainly puts greater pressure on countries like Russia that give cover and protection to the Assad regime.”
Matthew Schofield in Berlin and Anita Kumar in Washington contributed to this report.