At the end of Philadelphia Avenue in Washington a middle-aged woman with a weather-beaten face and a brown wig sits on a milk crate. Surrounded by placards calling for nuclear disarmament, she hands out cheaply produced leaflets to passers-by. This remarkable woman has been holding a vigil outside the White House day and night for 21 years - sleeping, in a sitting position, for just 3 hours a night, so as to avoid breaking the stringent DC vagrancy laws. It is impossible not to be moved by her conviction and moral rectitude; it is equally impossible not to be depressed by the futility of a cause which has robbed her of the best years of her life.
It does not take long for Americans to figure out that Concepcion Picciotto is European. Like Concepcion's faith in world peace, the European belief in multilateralism and the human rights of prisoners seems weak and unworldly - a luxurious delusion which post-9/11 America can no longer afford.
I went to Washington and New York last week to take the temperature of American foreign policy. It there was one theme that united policy-makers in the White House and State Department with academics and analysts from a range of think-tank and media perspectives, it was that America will only listen to Europe if we can come up with new arguments or strategies that will surprise and interest them.
The post-9/11 belief that Americans had learnt the necessity of multilateralism has been reversed; Americans seem to have learnt only the impatience and frustrations of a multilateral approach. Even NATO - practically the leanest and most targeted institution around - is seen as terminally bureaucratic.
A grizzled old hand like Marvin Kalb, a news anchor at NBC for two decades, described the new impatient mood: "Up until 9/11 we were willing to stay up all night and talk through the issues. Now people are not interested in your pious, well-intentioned advice. 9/11 was an intellectual slap across the head".
So Americans seems as little inclined to listen to lectures from European governments as from Concepcion's pavement protestors. So what should Europe do?
Tony Blair's answer has been to be unflinching in his public support for the United States. The left dismiss this as weak or opportunistic, and believe Blair is deluded in believing that such solid support will enable him to influence, or extract concessions, later. Does he really think Bush, Cheney and Rumsfeld will listen to him?
The latest dispute over steel shows that, though Condi Rice may have been reduced to tears by the playing of the star-spangled banner at Buckingham Palace, the Republicans' gooey sentimentality does not infuse their political strategy or weigh heavily when it comes to paying back domestic political constituencies.
Many Americans compared Blair's plight to that of the long-suffering Colin Powell - arguing about the detail and reluctantly making concessions in the hope that more influence can be exerted from the inside than by sniping from the sidelines. By its nature, this form of influence cannot win spectacular public victories. It seeks to work at the margins, in the tactics and implementation of policy rather than at a strategic level. But the complexity of US foreign policy-making, and the continued importance of the State Department in making and implementing this, has been understated in much recent media commentary.
Francis Fukuyama became famous for his confident belief in the global triumph of liberal democracy. He does not believe that the events of 9/11 change this fundamental analysis. But he tells me that the differences between us are about much more than policy or interests, they are existential: "The US and Europe come at international law from such different angles. Every country in Europe has been busy divesting itself of sovereignty with the Euro and Maastricht. Americans still have an abiding belief in American exceptionalism and sovereignty. The American government still thinks that sources of legitimacy are national and that there are no higher sources of legitimacy. The traditional concern is that a lot of international law has been made by governments which are less democratic than the US". In fact, Fukuyama claims that Americans are so suspicious of international law that they don't even think that Europeans themselves believe in it, "A lot of my friends think that Europeans do not really take GMOs or global warming seriously - they think these are just deliberate ploys to hobble America".
But other Americans cite examples of European influence. Joseph Nye - who was in the Pentagon during the Clinton era and now runs the Kennedy School at Harvard - thinks we need to pick battles in areas where we have some influence: "There is a tendency for Americans to think that Europeans don't matter. But - on the extradition of suspects, bargaining on the trade round, the fact that GE couldn't merge with Honeywell - they do. Europeans should remind Americans every now and again that if they want co-operation it is a two way street. There is a tendency to think that Europe is controlled by a bunch of whining lefties. So when criticism comes from unexpected directions - such as Chris Patten's recent outburst - it is more difficult to dismiss."
But Blair's apologia is not just aimed at the residents of the White House. The primary audicence is the rest of the world. It would be straightforward to stand aside with our principles intact while the US acts in a unilateral way. But that could have an even more corrosive effect on liberal internationalism than explaining and supporting their actions (even if you have to occasionally swallow hard). The idea of an international community based on rights and responsibilities is a public good - and one that Europe has more to gain from than anyone else.
The hard truth is that this international order, simply to exist, will continue to depend heavily on American power. So the legitimacy of this "European project" of creating a rule-based world order will remain umbillically linked to America's standing in the world. Blair is accused of simply supplying a multilateral fig-leaf for US actions, but the alternative may be no international legitimacy at all. This may be strategic tight-rope walking and nobody can be confident that it will succeed. Many American actions risk unpicking all the painfully extracted advances of the late 20th century - from the International Criminal Court and Kyoto to the WTO and Kosovo. But if the American administration remains unintertested in framing its actions in ways that appeal to wider audiences, it is safer for Blair to take on this role than let no one do it at all.
The European perception that this makes him simply cheerleader-in-chief is simplistic. This must be a three-pronged strategy; not simply an ambassadorial role. And at least as important as consultations on how to implement strategy is the humanitarian aftercare role that Europe can supply for military interventions. Some British diplomats and soldiers may bridle at a role that could be caricatured as international social work. But prevention and reconstruction is the vital part of the jigsaw which bores the Americans. This is where Europe has the capacity to make a meaningful contribution.
In many ways Europe's role in global society mirrors Germany's role in the development of the European Union. While France and Britain have asserted the national interest and bristled at the idea of becoming net contributors to the EU, Germany has made a long-term investment in the structures and quietly paid for the EU's development and smoothed the disagreements between its more nationalistic fellow member states.
Blair is riding sky-high in American opinion despite having slipped a principled universalism into the coalition's rhetoric. The necessary contradiction of his position - that he is supplying legitimacy for actions and events over which he lacks ultimate control - puts him in permanent danger of losing credibility. But his energetic attempt to square this circle has to be a better bet than principled irrelevance.
Mark Leonard is Director of The Foreign Policy Centre (www.fpc.org.uk) and editor of the forthcoming collection "Reordering the World: the long-term implications of September 11th". This is the first in a series of monthly online columns for Observer Worldview. You can email the author at mark@fpc.org.uk.
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