Until last night's extraordinary defeat of the government (the last time a prime minister lost a vote over an issue of peace and war was in 1782), Ed Miliband was facing one of the most politically dangerous decisions of his leadership. Having wisely refused  to either rule in or rule out the use of military action against Syria until after the UN weapons inspectors had reported, he would eventually have had to come off the fence. Either position would have been fraught with risk. Had he supported intervention (as seemed most likely), he would have faced a significant Labour rebellion with further frontbench resignations (shadow transport minister Jim Fitzpatrick stood down  in advance of last night's vote). Had he opposed it, he would have run the risk of being confounded by a successful operation.
Last night's parliamentary vote means he will now never have to decide. While there remains a hypothetical majority for military action (Labour's amendment would have passed had the Tories swallowed their pride and supported or abstained), David Cameron's decision to unambigously rule out intervention means it will never be tested. After Miliband asked him to reassure MPs that he would not use the royal prerogative to approve military action, he replied:
It is very clear tonight that while the House has not passed a motion, 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.
Miliband could have responded by promising to 'work with the Prime Minister' (as Labour List's Mark Ferguson suggests ) to secure a majority for Labour's stance: that military action should remain an option if "compelling evidence" is provided that the Assad regime was responsible for the Ghouta massacre. But in his post-vote interview with Sky News he instead chose to second Cameron's decision to take intervention off the table. He said:
Military intervention is now off the agenda for Britain. There would have been nothing worse than intervention without full international support.
Faced with a hostile PLP and a hostile public (just 22% supported military action), Miliband took the escape route offered to him by Cameron. While some interventionists will despair at the apparent lack of principle involved, his political logic was impeccable.
"When you decide, you divide" said Blair upon Thatcher's death. Miliband's great fortune is that he will never have to do so.
Update: In his latest remarks on Syria, Miliband has made it even clearer that, for him, military intervention is no longer an option. He said:
There are other routes than military means to actually help the people of Syria.
I don't think the Government should wash its hands of this issue.
I think all of the focus of the Prime Minister and the Government in the coming days needs to be working with our allies to find other ways to press President Assad, to take action with our allies to put the diplomatic, political and other pressure that needs to be put on the Government there.
We need the peace talks to get going. So there are other things the Government should be doing.