"There was a great deal of skepticism in the room about the utility, effectiveness and support that we would have for the kind of strike that the president has proposed," said Rep. Jim Himes, D-Connecticut. "There's not a lot of skepticism, frankly, about whether or not this was an attack carried out by the Syrian regime. While nobody would say that it's been proven, the vast bulk of the evidence suggests that this was an attack carried out by the Assad regime."
Sen. John McCain told CBS' "Face the Nation" that Obama had invited him to a Monday meeting at the White House to discuss the next steps in Syria. McCain, who has been pushing for military intervention in Syria, said he had questions for the president.
"I want to find out whether there is a plan and a strategy. I want to find out whether this is just a pinprick that somehow Bashar Assad can trumpet that he defeated the United States of America," McCain told CNN. "But I will say that if Congress overrules a decision of the president of the United States on an issue of national security, that could set a catastrophic precedent in the future. It would be a very dangerous precedent to be setting."
Global debate surges over Syria
At a meeting in Cairo Sunday, Arab League foreign ministers condemned the chemical weapons attack, urging the international community to take action and calling for the prosecution of those responsible.
"The Syrian regime bears full responsibility for the use of chemical weapons (in) this heinous crime," foreign ministers from the regional organization said in a statement, according to the state-run Saudi Press Agency.
"The council also called for providing the required forms of support for the Syrian people to defend themselves and the need for concerted Arab and international efforts to help them," the statement said.
Arab League Secretary General Nabil el-Araby said in a Twitter post that the league was calling for the United Nations Security Council to "assume its responsibility and take all the deterrent and needed measures against this crime and all crimes of genocide" in Syria.
But the statements Sunday did not directly refer to the United States, and it's unclear how much international support the U.S. government would have if it chooses to strike Syria.
At the Arab League meeting, Saudi Arabia called for international action, but Egypt said it was opposed to foreign intervention in the Syrian crisis.
Britain has voted against taking any military action in Syria, and France said it won't act without the United States as a partner.
German Foreign Minister Guido Westerwelle tweeted Sunday that the time gained waiting for U.S. congressional approval "must be used to reach a common position of the international community within the U.N. Security Council."
Amid the debate over whether to strike Syria, U.S. authorities are tightening domestic security measures. The FBI and the Department of Homeland Security are warning of a higher risk of cyberattacks after months of disruptions by hackers known as the Syrian Electronic Army, and authorities say more attacks are likely.
Opposition: Obama gave false hope
The shift to ask for approval from Congress left some analysts scratching their heads.
"The decision-making has been so confused and muddled that it's difficult to put the word 'wise' in front of anything they're doing right now," CNN's Fareed Zakaria said on Sunday. "The administration has hesitated between nonintervention and intervention, and it is caught between those two."
The Obama administration, Zakaria said, "seems to want to have it both ways, but it can't."
Others praised the president for taking a step to get more buy-in at home and abroad.
"Frankly, I think he looks prudent, and I don't doubt his resolve on this," John Negroponte, who served as director of national intelligence for two years under President George W. Bush, told CNN's State of the Union. "I don't think he's looking for an excuse to get out from a box or a situation that he painted himself into."
While some praised the president for giving Congress a chance to weigh in, a key group of Syrian dissidents said it was surprised and concerned by Obama's new approach.