There will be those who believe Thursday's vote in the House of Commons means that Britain cannot make a difference to the innocent civilians of Syria who are suffering such a humanitarian catastrophe. I don't agree. We must use next week's G20 meeting in Russia, with the eyes of the world on Syria, to seek to bring the international community together, and force the warring parties into the political solution that is necessary.
But the vote remains an important moment: for parliament, for the country and for Britain's relations with the world. This moment also gives us the opportunity to learn the right lessons for the conduct of foreign policy across all parties.
Some people have argued that the significance of this moment is that Britain is stepping back from its pivotal role in the world. There has been talk of a dark and depressing day. There have been warnings that Britain is slipping in to a narrow-minded isolationism, a doctrine that ill-serves the long-term interests of our country and threatens the peace and security of the world.
I do not agree with this. The British people know that we prosper as a country when we look out to the world, not when we turn in on ourselves. And the British people are willing today to accept our obligations to others, as we were when my parents were welcomed as refugees to these shores back in the second world war. And indeed, that is why there was a different response to the action in Libya two years ago, compared with the deep anxiety this week about potential action in Syria.
The British people do, however, expect our country's foreign policy to be conducted in a different way than it has been in recent years. Ten years on from the beginning of the war in Iraq, it is crucial to show that we have learned the lessons.
We remember how decisions then were reached on the basis of less than compelling evidence, with a rush to judgment that prevented UN weapons inspectors from having the time they needed to report. We should recall too that vital international institutions were bypassed at crucial moments. And we should remember that the consequences of military action were not thought through sufficiently.
This week, parliament demonstrated that we have begun to change in three important ways.
First, whereas the temptation for some was to move to judgment before the evidence was in, the country demanded a more reasoned and considered approach. When it comes to questions of war and peace, the British people rightly expect that the seriousness of our deliberations matches the gravity of the decisions we are asked to take.
They know that evidence should always precede decision, not decision preceding evidence. And however high the passions, the British people have the right to expect level-headed, calm and considered leadership.
Second, when it comes to questions of military intervention, it is clear that effective engagement with international institutions is essential. Britain must therefore always seek to work with the United Nations and in accordance with international law, not by dismissing the UN as at best an irritation and at worst an obstacle to our objectives.
Hard-headed but full-hearted engagement with the UN is vital both because it helps establish the moral authority of any recommended course of action, and because it ensures that such action has the very best chance of success. The UN security council is the forum in which Britain should seek to make its case to the world, test that case, and where effective alliances should be built. This does not rule out acting without the authorisation of the security council but in accordance with international law, as was the case with Kosovo. But seeking to work through the UN must be the essential precondition of any action.
People will ask what these commitments to calm, reasoned deliberations and effective multilateralism mean for our relationship with the United States. I believe the special relationship should and will endure.
Our shared history, values and institutions require nothing less. And there is no solution to most of the problems of the world, whether it is the Middle East peace process, climate change or Syria, which does not go through the United States. And as the president of the United States and his colleagues make difficult judgments with regard to the situation in Syria and other challenges in international affairs, Britain will always listen and engage.
What the events of the past week have shown is that, however close that alliance, on occasion Britain may take a different view. The British people rightly expect their parliament to reflect their views and concerns and represent the national interest.
Third, the public expect us to be open-eyed about the consequences of any action. A key difference in the motion we put forward in the House of Commons was that any action had to be weighed for its impact on the region. Part of the problem for many MPs on Thursday was that when these questions were asked, the answers were found wanting.
Nothing in the new era of foreign policy that I am describing leads to Britain stepping back from its international obligations or from its place in the world. Quite the opposite.
The proper lesson of the past week is that Britain's future does not lie either in turning in on itself or rushing into conflict without properly considering the consequences.
It lies instead in a hard-headed multilateralism, where crucial decisions about our foreign policy are made in a calm and measured way, working together with international institutions and in accordance with international law. That is a better future for Britain, and one that will make us stronger in the world.
Ed Miliband is leader of the Labour party and MP for Doncaster North.