Middle East - Shortly after 10 o'clock last Monday morning, US Secretary of State John Kerry acknowledged the scale of the difficulties facing the United States. President Barack Obama had decided to launch a punitive strike against Syria, following an alleged chemical weapons attack in an eastern suburb of Damascus, but he had also taken the surprising step of asking Congress to authorise military action.
A growing number of US lawmakers looked ready to vote the President down. Mr Obama had taken that decision to consult Congress "based on his gut". Speaking at a press conference in London, Mr Kerry said that the President "knew it would be tough".
Mr Kerry's performance was far from fluent. Somewhat strangely, he said that any military action would be "unbelievably small". But when a reporter from America's CBS network asked if there was anything the Assad regime could do to stop a US attack, Mr Kerry said something even more unexpected. "Sure," he replied. "He could turn over every single bit of his chemical weapons to the international community in the next week. Turn it over, all of it, without delay, and allow a full and total accounting for that. But he isn't about to do it. And it can't be done, obviously."
Throughout this week, those 50 words have been repeatedly dissected as the moment that stopped another US war. Four hours after Mr Kerry spoke, his Russian counterpart Sergei Lavrov responded. Russia, he announced, would propose to President Bashar al-Assad, its loyal ally, that he should hand over his chemical weapons to the international community for destruction.
The Russian offer had an electric effect. At the end of that day, Mr Obama was grasping at the Russian initiative, suspending his proposed missile strike and accepting negotiations with Moscow. The vote in Congress was averted. But at what price? The US has argued that, for the first time in the Syrian crisis, Russian President Vladimir Putin has given ground and is imposing demands on Mr Assad. But others argue that Mr Putin has outmanoeuvred Mr Obama with a masterstroke that will bog the US down, forcing Washington to negotiate an unrealistic plan to remove Syria's chemical weapons. Whoever is right, one thing is clear: the US should have seen Mr Putin's diplomatic coup coming.
Friday, Sept 6: A short talk in St Petersburg
To explain why, we must trace events back to Sept 6 and the concluding stages of the G-20 summit in St Petersburg's 18th-century Constantine Palace. For Mr Putin, the host, the event was a success. He had lined up many of the G-20 leaders to oppose a military strike. For Mr Obama, the event was dominated by a growing sense that Congress would prevent his attack.
The body language between the two was notably frosty. But as the final session ended, Mr Putin and Mr Obama settled into a corner of the main hall for a short conversation. Mr Putin focused on one question: Why not work on a joint plan to get Syria to place its chemical weapons under international control?
This was not the first time the two had discussed this. US and Russian officials say it was first raised at the G-20 summit in Mexico in 2012. Mr Kerry and Mr Lavrov have also talked about it several times over the past year. But the US had always viewed it with suspicion. Any plan to remove Syria's chemical weapons would be a challenge in the midst of a war. But the US also took the view that it was pointless discussing such an idea unless Mr Putin was prepared to force Mr Assad to the negotiating table, something Russia had failed to do. Mr Obama came away from the conversation agreeing, albeit rather vaguely, that the US and Russian foreign ministers could explore the idea. Leaving St Petersburg, he told Britain's Prime Minister David Cameron what Mr Putin had said. "But there was nothing concrete about it," said a Downing Street official. "It all seemed very notional. Nobody thought this would be a way out."
Nobody except Mr Putin. In his summit press conference that afternoon, Mr Putin warned that Russia would go to Syria's aid if the US attacked. But then he paused. "Incidentally," he said, "we have agreed on some possible scenarios designed to settle this crisis peacefully. We've agreed that Sergei Lavrov and John Kerry will be in touch in the near future to discuss this very sensitive issue."
Clearly, this idea was on his mind.
Sunday, Sept 8: A battle to win in Congress
Back in Washington, Mr Obama was focused on the impending votes in Congress. The White House drew up a campaign plan to win over lawmakers and a deeply sceptical public. Mr Denis McDonough, White House chief of staff, toured the Sunday morning television news shows to make the President's case. Arrangements began for Mr Obama to conduct back-to-back interviews with six TV networks the following night. The President would do a live TV address on Tuesday. All the signs were that Mr Obama was losing a big section of the moderate middle of his own party.
In the Kremlin, Mr Putin took no comfort from Mr Obama's troubles. He was determined that the US must not carry out this strike, believing it would inflame the Syrian civil war. Plans were therefore finalised to invite Syria's Foreign Minister Walid Muallem to Moscow. There, Mr Lavrov would spell out his plan to get Damascus to hand over its chemical weapons.
Some Western diplomats have a nagging question about Mr Putin's thinking. Why did he feel he had to act to stop Mr Obama's plan? He could have taken the view that Congress was probably about to do the job anyway. "Obama was in trouble," said a European diplomat. "Putin could have sat back and enjoyed the show on Capitol Hill. He clearly felt that Russia still needed to act."
Mr Putin has always taken the view that the US would ultimately be drawn into military action in Syria - as it has been in Iraq, Afghanistan and Libya. But one other factor may well have preyed on his mind. The UN was beginning to circulate the findings of its inspectors into the chemical attacks on Aug 21. Russia insists opposition rebels carried out the attacks. But the UN was letting it be known that it had found missile parts, suggesting that the Assad regime must have been culpable. One senior British diplomat said this would have loomed large in Mr Putin's calculations. "He must have taken the view that once the report was out, political momentum behind a US strike could only grow."
Monday, Sept 9: Moscow's plan goes public
On Monday morning, the international media focused on Damascus. Extracts of an interview by CBS with Mr Assad were emerging, with the Syrian President warning Americans to "expect everything" if the US were to attack. But while his words were defiant, events in Moscow were offering more clues about where the diplomacy was heading. At a joint press conference, Mr Lavrov and Mr Muallem avoided saying anything about their discussions on a plan to remove chemical weapons. But the Syrian Foreign Minister let slip that something was afoot. "Because we trust the Russian efforts, we will fully cooperate with Russia... in order to foil the pretexts used to launch (US) aggression."
No one in Moscow was yet saying what these "Russian efforts" were. But Mr Kerry would help provide the answer a few minutes later.
It is unclear why Mr Kerry mentioned the idea of Syria handing over its arms. He may have had the short discussion in St Petersburg in his mind. The idea had also been raised by European foreign ministers at a meeting with him in Lithuania the previous day. In any event, when the State Department was deluged with questions from journalists, Mr Kerry's aides played it down. "Secretary Kerry was making a rhetorical argument," one said. "His point was that this brutal dictator... cannot be trusted to turn over chemical weapons."
In Moscow, however, Mr Lavrov seized his chance. As the Secretary of State's aircraft left London, the Russian rang Mr Kerry. Mr Kerry insisted again that this had just been a rhetorical argument. But the Russian was insistent: He would launch an immediate proposal for Syria to hand over its chemical arms to an international body. Fair enough, said Mr Kerry, at the end of a 15-minute call. "But this is not a game. It has to be real. It has to be comprehensive."
According to one Western diplomat, Mr Kerry had effectively offered Russia a golden opportunity. Mr Lavrov feared that if he had launched the Russian proposal "out of the blue", it would have looked like little more than a crude attempt to derail the US. "Kerry's words gave Lavrov the cover he needed and a chance to present this as something consensual that the US and Russia had discussed," said the diplomat.
But the opportunity offered to Mr Obama was more substantial. At the White House, officials were parsing Mr Lavrov's words and coming to two conclusions. First, there were hard commitments from the Kremlin, not least requiring Syria to sign an international convention prohibiting chemical weapons. This could not be ignored. But the bigger implication was that, by signing up to the Russian proposal, a potentially disastrous confrontation in Congress could be averted. Mr Obama showed interest in Mr Lavrov's proposal in that night's TV interviews and redrafted his address for the following night. There was just one problem: the US and Russia were embarking on a proposal about which there had been only cursory discussion.
Wednesday, Thursday, Friday: A relationship reset?
As soon as the US accepted the proposal, diplomats in Washington, Moscow, Paris and London engaged in what one official calls "an almighty scramble". It is hard to think of any moment - certainly since the fall of the Berlin Wall - when the US and Russia have set out on such a big diplomatic venture without any technical groundwork being laid. "Nobody was ready," said Mr Romain Nadal, diplomatic spokesman for French President Francois Hollande. "Not even the Russians themselves. That was all too clear when the Russians called a UN Security Council meeting for Tuesday night and then ended up cancelling it."
Confusion reigned for much of the week. On Wednesday, France insisted there must be a UN Security Council resolution threatening "extremely serious consequences" if Syria refused to hand over its chemical stocks quickly. Russia baulked at what it deemed France's aggressive approach. On Thursday night, Mr Kerry and Mr Lavrov met in Geneva, accompanied by dozens of their countries' security officials, to hammer out the details of a UN resolution. In the meantime, chemical weapons experts have lined up to describe the task of destroying Syria's stockpile - the world's third-largest - as practically impossible in the midst of a civil war.
How might the events of the week ultimately be judged? For many, the verdict will be that Mr Putin has outplayed Mr Obama. By launching his initiative, the Russian President has achieved numerous aims: He has stopped a US military strike and taken Mr Obama down a tortuous diplomatic road. Above all, he has achieved something he has long sought: the chance to place Russia - and himself - at the centre of global diplomacy, presenting himself as indispensable to solving the crisis. "Lavrov deserves a raise," tweeted Mr Ian Bremmer, president of the Eurasia Group consultancy, describing an "extraordinarily effective promotion of his country's interests on the international stage".
Many will also judge that Mr Obama has emerged weaker. Over the past three weeks, he has zigzagged from one initiative to another. "I can't think of a foreign policy issue in my lifetime where America has offered us so little sense of strategy and such a strong sense of making things up as it goes along," said one British official.
Others will see this judgment as too harsh. For one thing, Mr Obama can argue that his initial threat of military action has forced Mr Putin to give ground on Syria, putting some heat on Mr Assad for the first time.
Moreover, events in the coming week may prove significant. The United States and Russia yesterday agreed on an ambitious plan to eliminate Syria's chemical weapons by the middle of next year, AFP reported. Russia also said the United Nations Security Council would act if Syria breached the international convention banning chemical weapons under the deal reached with the US, as the two countries seek a solution to end the civil war.