On the night when Barack Obama took Virginia, Maryland and Washington DC with 20 point leads, an equally potent primary result came in from Maryland's fourth congressional district. Away from the glare of the international media, Donna Edwards, anti-war campaigner and community activist, trounced eight-time incumbent Albert Wynn in the battle for the Democratic nomination. This was no minor achievement. A sitting congressman had not been ousted in a primary in Maryland for 16 years. In 2006, a high tide for anti-incumbent sentiment, Edwards lost to Wynn by 3%. But she persevered. Wynn had taken huge sums from lobbyists. He had voted for the Iraq war, Dick Cheney's energy bill and to repeal inheritance tax. Edwards argued that this was against the wishes and interests of his mostly black, middle-class constituents. Last month she beat him by 35%.
There is a symbiotic relationship between Edwards's victory and Obama's potential. To some extent, she rode his coat-tails. The surge in turnout - particularly among the young - and focus on "change" could only have swelled her numbers. But if the energy around Obama's candidacy is going to be translated into an enduring political reality, then he has more to learn from her victory that night than she does from his.
For her win was the product not just of electoral momentum but a political movement. For several years now online activists have been building a progressive counterweight to rightward drift within the Democratic party. In general elections, they attack Republicans. In primaries, they support progressives. And in between time they light a fire under Democrats lest they forget why they were elected.
Edwards was, among other things, a product of that movement. It made her candidacy viable and sustained it after her narrow defeat in 2006. If she goes to Congress and sells out, they will turn on her. If she delivers progressive policies and comes under fire, they will support her. The interests of her candidacy and their priorities coincided. But they are not identical.
As the primary race reaches its denouement, Obama needs to reflect on how he can nurture a similar relationship with his base - not just to sustain his candidacy but to bolster his prospects of actually delivering on his promises. Obama has been described as running a grassroots movement. This is only half true. It is certainly grassroots. In the various states that I have seen it operate there are plenty of local volunteers and local staff. At web-driven meet-ups people get together, independent of the campaign. On Facebook his candidacy has a life of its own. One of the reasons he has won every caucus state is because his supporters are far more dedicated and far better organised at a local level than Clinton's.
But it is not a movement. It has no purpose or meaning beyond getting him elected. Once he wins or loses it will cease to exist. It operates not from the bottom up but the top down. The change he refers to is principally a change in leadership. The chant "Yes we can", in essence, means yes he can.
When I asked a group of volunteers in Charleston who had just literally danced through the streets on Martin Luther King day, why they were so excited about his candidacy, they told me they could not answer without prior approval from head office 115 miles away in Columbia. It is always a troubling sign when politicised people lose their voice or hand it over to a higher authority.
This comes more by way of description than criticism. None of this is a problem for Clinton because she has never pretended she is running a movement (or if she did nobody believed her). Obama alludes to his need for broader support on the stump, regularly telling audiences "this election is not just about me" and "I cannot do this alone". But beyond electing him it is not at all clear where he imagines others will come from or how they would engage. There is little in the way his campaign works to suggest a vibrant, independent insurgency being reined in by headquarters.
What Obama does have is a highly professional electoral campaign that has proved itself adept at getting people involved at every level and harnessing new technologies to that end. So far so good. It is perfectly possible (although by no means inevitable) that by the end of tomorrow night Obama will effectively be the nominee. His team could be forgiven for dwelling on making that immediate prospect a reality.
But then what? If Obama is serious about his desire to fundamentally change the way America operates at home and abroad then he will have take on entrenched, vested interests to beat John McCain and deliver on his promises.
This would be a tall order in the best of times. And these are not the best of times. Whoever wins will inherit a nation in serious state of disrepair. Just in the last two months, since those first caucus goers ventured into the Iowa cold to deliver him his surprise initial victory, the Dow has fallen by 6% and the price of petrol has risen by 4.5%. Meanwhile Iraq is stalling, Afghanistan is unravelling and the former chief prosecutor for Guantánamo's military commissions, Colonel Morris Davis, has conceded that the trials of detainees there are rigged. Taking over from George Bush is a bit like becoming the new manager of Leeds United or chief executive of Northern Rock. You enter with high hopes pinned to your front and "kick me" on your behind.
An electoral coalition of independents, wealthy progressives, African Americans, white men and the young have come together to vote for him, but has yet to mobilise itself into a political movement that can support him. A movement sparked by the issues his candidacy has raised that moves beyond his personality as a candidate.
Were he to win, he would need to tap their outrage at the pharmaceutical companies, Halliburton, lobbyists, Pentagon torturers and corporate tax-dodgers. He would need them sufficiently empowered to confront the banks over their lending practices, multinationals over outsourcing, and universities over rising fees. And in his negotiations with Congress and other powerbrokers he would need to know the limits to what he can concede without antagonising his base.
Obama cannot turn this around on his own any more than Bush got America into this mess on his own. Enough of the public had to be actively complicit in the Bush agenda for it to be possible to make things this bad. Indeed, the right has been extraordinarily adept in this regard. When Bush nominated Harriet Miers or sought to pass immigration reform, they blocked him. When he cut taxes and started war, they backed him. Without them his presidency would have crumbled sooner, and even more dramatically. Enough of the public would have to be equally complicit in Obama's agenda for him to right Bush's wrongs.
But the White House is where that process ends - complete with signing ceremony and fanfare - not where it starts. Tomorrow Obama will once again be running. If he is to be successful, not just electorally but politically, his supporters will have to make sure they do not stand still.
Gary Younge is a Guardian columnist and feature writer based in the US. He was formerly the paper's New York correspondent. His most recent book is Stranger in a Strange Land: Encounters in the Disunited States; he is also the author of No Place Like Home, published in 1999
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