Yesterday's summit meeting between President George Bush and Mr Tony Blair addressed but did not resolve what is undoubtedly the most important political question arising from the war in Iraq - the role of the United Nations in governing that country after the fighting is finished.
The two leaders agreed the UN will have a role and the importance of an Israel-Palestinian settlement. They stressed the urgency of reactivating the oil-for-food programme. But they have different perspectives on what that role will be. Many of the details remain to be worked out.
At the core of this issue is who will control post-war Iraq. Will it be the Anglo-American led coalition which has used force despite the Security Council majority opposed to it, based on their victory - on the large and increasingly unrealistic assumption that they will do so relatively quickly and with not many more casualties? Or will the UN's authority be restored by Security Council resolutions endorsing the post-war governing arrangements, protecting Iraq's territorial integrity and providing humanitarian relief? This is the difference between an outcome based on rights established by invasion and occupation and one based on international legitimacy.
The balance struck between them will determine the shape of international order elsewhere for years to come. That is why yesterday's encounter was so important and why the humanitarian programme so urgently needed to prevent civilian deaths and suffering has itself become politicised over who should control and endorse it. Arguments within the Bush administration over the proper role of the UN have alerted other governments to the deep significance of how these questions are resolved. On their outcome will depend the credibility of Mr Blair's own role as a transatlantic bridge builder and his political future in Britain. His open acknowledgment that they have to be addressed frankly, and resolved, is welcome; but on the evidence of yesterday's meeting there is a long way to go.
Undoubtedly this is due to the fact that the primary objective facing President Bush and Mr Blair is to win the war they have started. Their refusal to speculate about how long this will take, but only to insist it will be achieved, implies it could be much more long-drawn-out than they originally assumed. A major factor at play in the first week of the war is that many Iraqis oppose the invaders more than the regime, a sentiment that will bolster and prolong military resistance. That in turn affects Saddam Hussein's political and military strategy - to play for time, draw fighting into the major cities and seek to turn Middle Eastern and world opinion against a stalemated war with huge civilian casualties. Events in the field and the great uncertainty of all-out war will therefore continue to determine political positioning about a post-war settlement. But that settlement must give the UN the central role in determining Iraq's political future.