President Obama could still launch air strikes on Syria despite David Cameron's historic reversal in Thursday's Commons vote, according to the White House.
Subsequent to the British vote, Caitlin Hayden, speaking for Obama's National Security Council, said that the US would now consider going it alone, emphasising that the president would still do "what is in the best interests of the United States".
Following the British government's surprise loss, Cameron immediately ruled out any UK involvement in military action against Syria. Rarely before has a British prime minister been so spectacularly defeated on a matter of foreign policy, raising questions not only about Cameron's premiership and the future of the so-called "special relationship", but also the likelihood of Washington intervening unilaterally against President Assad for his alleged use of chemical weapons.
Following the debate, Cameron told MPs: "I strongly believe in the need for a tough response to the use of chemical weapons. But I also believe in respecting the will of this House of Commons. It is clear to me that the British Parliament, reflecting the views of the British people, does not want to see British military action. I get that and the Government will act accordingly."
Obama was already reeling from a lack of congressional support before London's stinging rebuke, while questions of evidence and international legality, echoes of the build-up to the 2003 conflict in Iraq, hang uneasily over the muted conflict.
Will Obama dare strike Syria without British backing?
Earlier, Josh Ernest, a White House spokesperson, had conceded that the US might be willing to launch unilateral action as the proposed international coalition - Britain, France and the US - started to look less firm.
Reported by the AFP, Ernest said: "We certainly are interested in engaging with the global international community on this issue. But at the same time, the president's chief accountability is to the American people that he was elected to protect. The president believes strongly in making the kinds of decisions and taking the kinds of steps that are necessary to protect our core national security interests that we've acknowledged are at stake in this situation."
Yet on Thursday afternoon, Diane Feinstein, the chairman of the Senate intelligence committee, had highlighted the importance of the UK in America's planning on Syria. "I think if the President were to decide to go there's a very high likelihood that the United Kingdom would be with us," she told Time Magazine, adding: "I think the UK makes a difference."
Protesters gather outside the Houses of Parliament on Thursday
With news that the British were now out of any military move against Assad, Republicans and commentators lined up to make political hay from the president's seeming inability to corral what has historically been its most dependable ally.
Donald Rumsfeld, the former Secretary of State and one of the architects of the 2003 Iraq War, described the British vote as "humiliating for Obama", citing the President's dithering (and not the shadow of the previous conflict) as the reason why the British Parliament had blinked.
Syndicated columnists Charles Krauthammer echoed Rumsfeld's sentiments. He told Fox News: "It is a complete humiliation for the Obama administration. Forget about the merits about what Obama wants to do, this involved the elementary conduct of international diplomacy, trying to get some allies together so we don't have to move unilaterally and who is the main ally who have been with us in every trench for the past 100 years? The British and now the British have voted against us."
The UN inspectors currently in Damascus are due to leave the country on Saturday. If Obama were to give the order to strike, it is unlikely to happen before they've presented their report on last week's alleged chemical attack.