It was a stunning about-turn from Barack Obama to seek Congressional authorisation for air strikes on Syria, but in hindsight it was clear as early as Friday afternoon that all was not well at the White House.
Just minutes after John Kerry, his secretary of state, had given that thunderous lunchtime speech warning that there would be "no end to the test of our resolve" if the Assad regime went unpunished for using chemical weapons, Mr Obama's own resolve already appeared to be waning. Speaking only minutes after Kerry had apparently made a cast-iron case for war, it was a diffident Obama who spoke, choosing not to take to the presidential lectern, but to offer a brief aside before a low-key meeting with the presidents of Latvia and Lithuania.
"A lot of people think something should be done but nobody wants to do it," observed Obama, betraying doubts that, it now emerges, had been steadily growing during one of the most turbulent weeks of his entire presidency. For those who knew where to look, there had been warning signs.
All week, observers noted the disparity between the stentorian pronouncements of Kerry and the lawyerly observations of Obama, but few - including Kerry, it seems - had realised how seriously Obama was starting to doubt the wisdom of going it alone. The week that ended in an about-turn began with a moment of clarity, aides told The New York Times, when Obama sat down with advisers on Saturday to review the horrendous videos of children writhing and dying in Syria. "When I was talking about chemical weapons, this is what I was talking about", the president said, stopping short of a decision to take military action, but making clear that some action would need to be taken.
On Monday, Kerry reflected that new momentum, talking of the "moral obscenity" of the Syria regime and promising "accountability". But on Wednesday, even as warships were being deployed to the Mediterranean, Obama again betrayed his doubts, giving an interview to US public television in which he appeared stressed and spoke tepidly in comparison to the ire of Mr Kerry and William Hague. Any action against Assad would be "limited, narrow", and amount only to a "shot across the bows", he said, admitting once again that there were "no good options" in Syria.
And then on Thursday came Cameron's shock defeat in the Commons that leftObama facing the prospect of taking action without the UN, without Nato and now without his most trustworthy ally. By Friday night those nagging doubts had swelled into a plan of action that would surprise everybody. "He had been kicking the idea around his head for days," one aide told CNN, but it was not until Friday evening, just after 6pm, that Obama confided his intentions with Denis McDonough, his chief of staff, during a 45-minute walk around the South Lawn of the White House.
Aides said that the combination of David Cameron's defeat, Congress's demands for a vote, unfavourable public opinion polls and Mr Obama's own belief in the need for consultation before strikes, which he had espoused as a presidential candidate in 2007, had all played a part. Returning to the Oval Office at 7pm, photographs released by the White House show Mr Obama huddled with his closest personal aides, including Mr McDonough, and Susan Rice, his national security adviser, as he announced his plan to seek Congressional backing.
"I have a pretty big idea I want to test with you guys," he said to the group, according to a White House aide quoted in The New York Times, and then proceeded to lay out the rationale for seeking backing from Congress. Several of those in the room, the Associated Press reported, argued against Obama, warning of the risks of asking for the backing from Congress, particularly the Republican-controlled House of Representatives. The president was not persuaded, however, and at 9pm on Friday Obama picked up the phone to Kerry; Joe Biden, his vice-president and Chuck Hagel, his defence secretary, to tell them of his decision.
To the outside world, however, air strikes still seemed imminent on Saturday morning as cameras caught Biden and secretaries Kerry and Hagel entering the White House in casual dress, for a meeting in the Situation Room with the President and the principal players. But behind closed doors, after more discussion and further talks with Congressional leaders from both parties, the final decision was being made not to act - at least not for now.
The president's decision left many stunned. While Congressional leaders formally welcomed the consultation, those who had looked to Obama for action saw not wisdom or leadership, but trademark indecision from a president who has long "led from behind" on foreign policy. "He looks completely indecisive and weak right now," a Senate aide told The Daily Telegraph after the announcement, "If he loses the vote, I truly fear for our national security. If he wins the vote, whatever strike follows will seem a hollow afterthought."