The White House has sent Congress a draft of a resolution seeking approval for a military response to "deter, disrupt, prevent and degrade" the Assad regime's ability to use chemical weapons. The Senate will hold hearings next week so a vote can take place after Congress gets back to work.
The president's strategy carries enormous risks to his and the nation's credibility, which the administration has argued is on the line in Syria. Obama long ago said the use of chemical weapons was a "red line" that Assad would not be allowed to cross with impunity.
British Prime Minister David Cameron charted a similar course last week by asking the House of Commons to support military action against Syria, only to suffer a stinging defeat.
Across the Atlantic, Obama's speech sparked calls for French President Francois Hollande, who supports an armed response against Syria, to seek parliamentary approval before taking military action. Hollande is not constitutionally required to do so. France's parliament is scheduled to debate the issue Wednesday, but no vote is scheduled.
For some in Syria's opposition who had put great hope in U.S. strikes, Obama's decision to postpone proved a source of despair and prolonged the torment of when — and if — Washington will act.
"Obama's speech yesterday made us feel worthless," said 29-year-old Damascus resident Nasib, who gave only his first name for fear of reprisals.
"The government here doesn't care, they're genuinely not scared, they're not gloating. So it's only provocative to us people who sit here scared, not knowing when to expect the strike," he said. "I had to tape my windows so they wouldn't break. I know people who prepared sleeping pills to give to their kids the night of the attack so they can sleep and not be scared."
For others, Obama's choice was seen as simply business as usual from a country that they say has done nothing to halt the massive trauma and bloodshed gripping Syria.
"We weren't putting too much hope in the U.S strike," said Mohammed al-Tayeb, an opposition activist in Eastern Ghouta. "America was never a friend of ours, they're still an enemy."
In the buildup to the potential strikes, the opposition and Damascus residents say the Assad regime moved it troops and military equipment out of bases to civilian areas.
The main Western-backed opposition group, the Syrian National Coalition, said in a statement Sunday that the army repositioned rocket launchers, artillery and other heavy weapons inside residential neighborhoods in cities nationwide.
Two Damascus residents confirmed the regime troop movements in interviews with The Associated Press. One woman said soldiers had moved into a school next to her house and she was terrified.
With U.S. and French strikes no longer looming, the U.N. probe into the attack has more time to analyze samples it took during on-site investigations before the specter of military action returns.
The head of the U.N. chemical experts' team, Swedish professor Ake Sellstrom, is to brief Ban later Sunday.
The inspectors left Syria on Saturday and arrived in The Hague, Netherlands. The samples they collected in Syria are to be repackaged and sent to laboratories around Europe to check them for traces of poison gas. The U.N. says there is no specific timeline for when their analysis will be completed.