In a separate interview with NBC, the president took the step - unusual for any politician - of conceding he may lose his campaign in Congress for legislation authorising a military strike. "I wouldn't say I'm confident" of the outcome, he said.
"I think it's fair to say that I haven't decided" on a next step if Congress turns its back, the president told NBC, part of a furious lobbying campaign aimed at winning support from dubious lawmakers as well as a war-weary public.
The president picked up a smattering of support but also suffered a reversal when Sen. Johnny Isakson, a Georgia Republican, announced he had switched from a backer of military action to an opponent.
"They're in tough shape. It is getting late," said Rep. Peter King, R-N.Y., after he and other lawmakers emerged from a closed-door meeting with administration officials. The New York Republican favours the legislation that Obama wants, but he said the president didn't need to seek it and now must show that a strike "is in America's national security interest."
Classified briefings for lawmakers just back from vacation, the public release of cringe-inducing videos of men, women and children writing in agony from the evident effects of chemical gas, and a half-dozen network news interviews featuring Obama were folded into the White House bid to avert a humiliating defeat over the next 10 days. Obama met with members of the Congressional Black Caucus during the day, and arranged a trip to the Capitol as well as a prime-time speech from the East Room of the White House on Tuesday.
In the Senate, Reid said he had discussed a delay in Wednesday's scheduled initial vote with the president.
Earlier, Reid had spoken strongly in support of the president's request.
"Today, many Americans say that these atrocities are none of our business, that they're not our concern," the Nevada Democrat said of Assad's alleged gassing of civilians on August 21. "I disagree. Any time the powerful turn such weapons of terror and destruction against the powerless, it is our business."
Others came down on the other side of the question.
"I will vote 'no' because of too much uncertainly about what comes next," said Sen. Lamar Alexander, a Tennessee Republican. "After Step A, what will be steps B, C, D and E?" he added, reflecting concerns that even the limited action Obama was contemplating could lead to a wider war. Missouri Republican Roy Blunt also announced his opposition.
In the House, one of two female Iraq war veterans in Congress announced opposition to military strikes.
"As a soldier, I understand that before taking any military action, our nation must have a clear tactical objective, a realistic strategy, the necessary resources to execute that strategy, including the support of the American people, and an exit plan," said Rep. Tulsi Gabbard, D-Hawaii. She said Obama's plan "fails to meet any of these criteria".
Legislation approved in the Senate Foreign Relations Committee last week would give Obama a maximum of 90 days to carry out a military attack, and it includes a ban on combat operations on the ground in Syria. Both of those limitations were last-minute concessions to critics of a military option, and it was unclear whether Reid would seek additional changes to build support.
Despite the difficulty confronting Obama, an AP survey indicated the issue was hardly hopeless for the president, particularly in the Senate where Democrats maintain a majority, and perhaps also in the Republican-controlled House.
The survey showed 23 Senate votes in favour of military authorisation and 10 more leaning that way. Opponents totalled 20, with another 14 leaning in the same direction, with the remaining 33 senators undecided or publicly uncommitted. That created at least the possibility of the 60-vote majority that will be necessary to advance the bill.
In the House, there were fewer than a dozen declared in support and 150 opposed or leaning that way. But 201 lawmakers had yet to take a public position, more than enough to swing the outcome either way.
The public opinion polling was daunting for the president and his team.
An Associated Press poll showed that 61 per cent of those surveyed want Congress to vote against authorisation of US military strikes in Syria and 26 per cent want lawmakers to support such an action, with the remainder undecided.
Adding to the uncertainty of the debate in Congress was a flurry of diplomatic activity that offered a potential way of achieving US aims without military action.
Reacting quickly to a comment made by Secretary of State John Kerry in London, Russia called on Damascus to surrender control of its stockpile of chemical weapons and Syrian Foreign Minister Walid al-Moallem said he welcomed the proposal.
At the White House, Obama's deputy national security adviser, Tony Blinken, said the administration will "take a hard look at" the proposal. "We're going to talk to the Russians about it," he said noting pointedly that it comes in the context of threatened US military action. "So it's even more important that we don't take the pressure off," he said, urging Congress to give Obama the authority he seeks.
Other officials sought to tamp down any suggestion that Kerry was making an orchestrated effort with Russia to avoid the strikes.
- AP
