So, after a tumultuous political week dominated by the government defeat over Syria, which Britain do we inhabit now? Is it the free-at-last nation which is "no longer a plaything of the US military adventure," as one Labour MP put it on Friday. Or the humiliated irrelevance which awoke that day with "the international credibility of Luxembourg", as a Daily Telegraph blogger suggested. The reality, as soon as you think about it, is neither of them.

There is no doubt, however, that Thursday night's Commons vote on Syria was a major parliamentary moment. Prime ministers do not often put their foreign policy on the line. They get rebuffed by MPs even more rarely. Thursday's 272-285 defeat for David Cameron's watered-down Syria policy has few precedents. It is as big a defeat as the modern Commons has delivered to any PM on a foreign policy issue. It should not be belittled, least of all by Mr Cameron. But nor should it be exaggerated.

The first question is: where does Thursday leaves Mr Cameron? The answer is that he is in much the same place he was in on Wednesday, though with a big and largely self-inflicted new political bruise. When earlier prime ministers lost the confidence of MPs over foreign wars, they had to resign. As the result was announced on Thursday there was a solitary diffident Commons call for Mr Cameron to quit. Neither his own party, nor his coalition partners, nor even Labour, wants Mr Cameron's head. His standing has taken a big knock, at home and away. But the next election has not got a single day closer as a result of the vote.

It is not even certain that British policy towards Syria has done a total U-turn either. Yes, Mr Cameron was very quick to say after the vote that there would be no military action when he could have simply promised a second vote later. Yet all three main UK parties still support in principle the case for strong action against Syria over the use of chemical weapons. What should MPs do if the case that John Kerry made in Washington yesterdayon Friday is solidly proven, or if the Assad regime launches another mass chemical attack or if al-Qaida does the same? Still vote to stand aside? Perhaps. Or press for action in the generally cautious terms promoted in the Commons this week? It is not necessarily inconceivable for the issue to be back on the table at some later stage and even to win some form of Commons backing.

There is no evidence that British public opinion has turned isolationist. There is plenty of evidence that it is fed up with the debilitating post 9/11 years of national sacrifice, with the humiliating excesses of US national security policy (not least its abuses of human rights and surveillance), with the unequal burden-sharing among allies and, above all, with the failures of policy. Iraq casts a very long, very dark shadow. As a result, right from the start of its spiralling civil war, Syria has felt like a sacrifice too far. When the latest call to arms came, though it came from a respected American president and was provoked by clearly intolerable war crimes, the answer was a clear one. Enough.

Mr Cameron made a massive miscalculation this week. But he is not the only one who has had a wake-up call. So have the Foreign Office and the armed forces. So have the intelligence services and the government lawyers. All of them have something tough to absorb about public tolerance for dangerous military engagements in hostile environments which, ever since Iraq, have felt variously precipitate, illegitimate, excessive, costly, unfocused and even, in the end, not really our fight either. Should we feel ashamed about these limits of national will, as Paddy Ashdown said yesterday? No. We should feel ashamed that our instinct for legitimacy and our patriotism have been too often and too cheaply taken for granted. It is not the public's credibility on the line. It is the government's. The mood is not never again. The mood is not now, not again, not like this.