David Cameron's plans for military action in Syria defeated at Commons vote.
Following one of the most sensational political upsets for decades, David Cameron was counting the costs of a shock Commons defeat over his planned action against Syria.
This saw him losing control of his party, his foreign policy and perhaps even his own future plus a bombardment of headlines that make for prime ministerial nightmares.
Politicians on all sides, crucially including 30 Tories and nine Liberal Democrats, flatly rejected his call for military action against Assad and instead chose to reflect the overwhelming public opposition to such action.
What surprised many was that the prime minister so fatally misread his own party and appeared to have no inkling of what was about to befall him.
The upshot, which he did instantly grasp however, was that any strikes against Damascus by others will have to proceed without UK involvement.
But the consequences of Thursday's surprise late-night defeat will be felt for years and go way beyond the single issue of this one planned military intervention.
Judging by his words, Cameron clearly still hopes it will happen, albeit without his involvement at any stage.
There will be knock-on effects for other countries struggling to convince their voters of the rightness of action, notably the US and France.
Ed Miliband gained huge kudos for toughening Labour’s stance against military action.
The huge impact on the prime minister's already diminished authority will be felt both at home and internationally, and there will be questions over what the vote means in terms of the sort of country the UK wants to be.
The constitutional right a prime minister has to use his executive power to launch actions without consulting parliament has also been ended for good, barring the most exceptional circumstances demanding an instant decision.
Labour fights back
Opposition leader Ed Miliband, who was widely hailed for having pulled off a major political coup by forcing Cameron into major concessions before the vote, did not escape the debate unscathed either.
His own proposal was also defeated and one of his junior ministers resigned over his leader's refusal to rule out military action at some stage.
His approach continued to prompt fury in No10 with claims that he had been playing politics with the issue. Defence secretary Phillip Hammond even suggested his actions had given "succour" to Assad. But Miliband's leadership has, nonetheless, been significantly strengthened by his calculated approach to the affair
There will be plenty of hyperbole over the next few days and sooner or later there are bound to be question marks over Cameron's future premiership. There is no doubt he has been massively weakened by the defeat.
He will no longer be able to accuse Miliband of weakness and lack of control. Those Tory MPs who have never supported his leadership have had their arms strengthened and he is facing a 2015 general election campaign, already pretty much under way, with a significant weak spot in his armour.
Lame duck leader?
The words "lame duck leader" and "broken-backed premier" have already been bandied about in Westminster and there are those across the political divide who question whether Cameron will even survive until 2015.
There are certainly plenty of Tory rebels who have never forgiven him for failing to win in 2010 and who have always wanted him replaced. And there are candidates waiting in the wings - London mayor Boris Johnson, Home Secretary Theresa May and former defence secretary Liam Fox to name just a few.
Any future talk of the much hyped "special relationship" with the US administration, already less special than for some years, will now prompt wry smirks at best. And global leaders will wonder whether the British PM can be relied on to deliver his parliament in future crises.
There will be some soul-searching over what signal the vote has sent to the world about Britain's role in international affairs.
Lord Paddy Ashdown, the former Liberal Democrat leader and high representative for Bosnia, has already expressed his dismay, saying he feels "ashamed" of his country's position and fears that Britain, already retreating from the EU, is heading for isolationism.
Looming shadow of Iraq and Blair
Perhaps one positive effect might be to see some serious re-examination of the role and constitution of the UN which, time and again and largely thanks to the 15-member Security Council, has proved to be a roadblock rather than a help when it comes to enforcing international law.
For many, it is in danger of going the same way its predecessor, the League of Nations, without some pretty radical, democratic reform.
But, once all this smoke has cleared, British politicians will be left surveying a political landscape that has fundamentally shifted. And really, all because of two words - Iraq and Blair.
Those two words hung over the entire Commons debate. Cameron recognised it when he stated that the well of public opinion had been poisoned by the Iraq affair, the dodgy dossiers, false claims, missing weapons, questionable intelligence and dubious legality.
Voters no longer trust their leaders to get it right over such military actions and, worse, probably don't believe what they are told by them in any case.
And, despite all the claims this was not Iraq II, there were just too many parallels between what was being asked of parliament and the voters over Syria and what they were told about Iraq a decade ago.
Whether those old wounds can ever be healed will be central to the way that not only Cameron, but all future prime ministers, will be able to craft a British government's foreign policy.
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