Standing at the edge of the area reserved for Obama's people in Grant Park, Chicago, I had a good view of the President-elect as he gave his victory speech, but a much better view of the campaigners who had brought about this extraordinary victory, which was just sinking in around me.
The evening was radiant and glorious, but it's wrong to see this simply as the triumph of African-American blood or the finishing line of some long ideological march. 'Yes, we can' is a political slogan, but it is also the activist's chant, and what I saw on a lot of the faces was hard practicality and the know-how of civic activism.
The night before I spent some time at the 'Last Call For Change' event in the Democrats' temporary quarters in Illinois Street, Chicago. The 150 volunteers crammed into the hot, airless space weren't new to this game. Like Obama, who once worked in the city's deprived South Side, these people were veterans of campaigns to improve schools, the cleaning up of wasteland and the alleviation of the unbearable poverty that startles the stranger's gaze in so many big US cities. Twenty-four hours later they were the ones who cheered hardest when Obama talked about harnessing energy, creating jobs, building schools and looking after 'not only ourselves, but each other'.
As someone who has come late to political activism of a sort, that seems to me to be the single most important part of the transformational campaign. It is amazing to me that so many conservatives in America, and to a lesser extent in Britain, have not yet grasped that, while the Obama campaign championed rights, it also placed an equal emphasis on civic commitment, which is at the heart of his appeal. He is not the Obi-Wan Kenobi of liberals, as they tried to portray him, not a dangerous leftie or the champion of command economy reform. He is a practical man who shrinks from the individualism that was spawned by Sixties liberalism, nurtured by Margaret Thatcher's influence and encouraged by the Bush administration as a strategy of social abdication.
The philosopher Michael Sandel, quoted in the New York Times last week, talked about the multiple crises facing the President-elect. 'The challenges are so great,' he wrote, 'that he will only succeed if he is able to articulate a new politics of the common good. In this election the American people rejected narrow notions of the common good ... Obama will have to reinvent government as an instrument of the common good - to regulate markets, to protect citizens against the risks of unemployment and ill health, to invest in energy independence.'
The trick will be to move the ethic of local activism into the decisions of national government; and that, oddly enough, may be aided by the realisation that has dawned during the financial crisis that most of us had been looking after ourselves, rather than each other. What only a few saw was that easy credit and the illusion of wealth encouraged political disengagement. Politics became collusion between policy-makers, opinion-formers who were too interested in cosying up to power and the self-interest of the majority, which, as a friend of mine wittily put it, saw the business conducted in Washington and Westminster as no more interesting or relevant than the work of a utility company. Government was way out there doing its thing unseen and damned near unscrutinised.
It explains how the Bush administration passed so many laws that would obviously damage the environment, for instance the mountaintop removal by the coal companies in Kentucky, and why in Britain neither the widening gap between the rich and poor nor the attack on constitutional rights caused much alarm. We were too busy getting and spending cheap money that was stolen from the future.
The age of Obama will bring forth many pieties, but the truth is that activist politics of the type practised by the people I met in New York and Chicago is obviously more concerned with the common good than self-interest and to that extent we witnessed a real transformation in the United States last week.
I was more moved than I can say by watching the people in that Illinois Street basement as the minutes ticked away to the polls opening on the East Coast. There was something more than just the commitment of the party faithful on display - a determination that the other side of the American character would get a chance to express itself and influence the decisions of government.
As Sandel wrote, 'Obama's campaign tapped a dormant civil idealism, a hunger among Americans to serve a cause greater than themselves, a yearning to be citizens.'
You can almost hear the ghost of HL Mencken ('Democracy ... is the worship of jackals by jackasses') chuckle at the hopes being expressed in the US media. With the exception of Fox News, which never lost its sneer and on election night gleefully ran footage of someone in the crowd outside the White House waving a red flag emblazoned with the hammer and sickle, most TV networks and newspapers fell into a swoon.
I would suggest that this is more a measure of disdain for the Bush government and what it has done to America's reputation abroad - something about which Americans really mind - than the expression of naive and witless hope.
Everyone knows the problems are unprecedented in scale. When the crowd in Grant Park began to shout out 'Yes, we can', Obama adroitly damped down the enthusiasm. And everyone knows that disappointments lie along the way, but at least we can take heart from the re-engagement of Americans with politics.
It was a night to remember, but I did have one doubt as I stood in the unseasonable warmth of Grant Park and that concerned the memory of a similar rally on the South Bank in London on 1 May, 1997, when a victorious Tony Blair was greeted by jubilant supporters. As he took power and showed himself, in Asquith's words, to be such a 'good butcher', the political classes dropped their guard and seemed to stop paying attention to what he was doing. Obama is a talented politician and, like Blair, he ain't no pussycat. He needs to be kept up to the mark by the activists who brought him to power: only with that scrutiny will he serve the common good.