In a major shift of policy, the United States this week decided to seek a new United Nations Security Council resolution as a mandate for expanding the US-British led force occupying Iraq.
Recent events have underlined the deteriorating security situation there, growing Iraqi resistance, and the failure to restore basic infrastructure and begin reconstructing the country.
More troops are needed with a greater international legitimacy and more expertise in nation-building and peacekeeping. But the countries capable of supplying them are insisting, quite correctly, on a more ambitious and far-reaching reconfiguration of the post-war political regime in Iraq than the United States is so far willing to consider.
Negotiations in coming weeks will clarify and possibly resolve these issues, but they promise to be difficult for all concerned. The Bush administration has had to swallow its pride in seeking a new resolution, after many of its leading figures dismissed the UN or sought to marginalise it. Understandably, states such as France and Germany are unwilling to agree to a change which would maintain US control of Iraq's political future, or to provide troops without sharing control of security. Nor are they willing to accept indefinite occupation without a much more clear commitment to restoring Iraq's sovereignty and political independence. US control of Iraq's oil resources and economic reconstruction is also being brought into the equation.
The French foreign minister, Mr Dominique de Villepin, has made much of the running in these arguments. But he also made the valid point that "in a world of peril and interdependence part of our shared destiny is being played out today in Baghdad".
It will suit nobody's interests to see Iraq disintegrate or become the focus of a wider regional instability. Those who opposed the war must nonetheless accept it created a new set of realities to be addressed.
India, Pakistan and Turkey have been identified as states with the military capacity to supply the necessary numbers of troops, while France, Germany and Russia among the Europeans are clearly in a position to do so. Different conditions may be acceptable to different groups of states.
This weekend's informal meeting of European Union foreign ministers gives an opportunity to work towards a common position, after the divisions created by the war. The latest opinion polls show there is widespread support among Europeans - and Americans - for a greater EU role if the political conditions are right.