The Obama campaign is squandering that most rare of commodities in politics: belief.
Back in 2006, Obama gave a speech in which he observed that "America is desperate for leadership. I absolutely feel it everywhere I go. They are longing for direction and they want to believe again." This phrase is perhaps the key to understanding Barack Obama's appeal during the Primaries.
Obama was "other", not racially, but politically. He defined himself in opposition to the familiar faces of American public life: anti-Clinton, and anti-Washington, he offered people the vision of a "new politics". This new politics was centred not on a policy agenda, but on the figure of Obama himself, and his ability to inspire a generation who are looking for something, or someone, to believe in.
The importance of this idea to his campaign cannot be underestimated: the banner across his campaign website reads, "I'm asking you to believe. Not just in my ability to bring about real change in Washington. I'm asking you to believe in yours." The very essence of the Obama candidacy is that Americans want to "believe again," and that he offers them that opportunity.
It is the extraordinary success of this "audacious" strategy, born out of Obama's own understanding of the contemporary American psyche, which makes his move to the centre so surprising and so potentially damaging.
The electoral calculation is both traditional and transparent: the campaign can move to the centre ground, where most voters are located, safe in the knowledge that their base are going to come with them because they are Democrats to the core.
In doing so, they aim pre-emptively to blunt Republican lines of attack on national security (FISA, Iraq), on social issues (abortion, death penalty, faith based initiatives), on trade (NAFTA), and foreign policy (Jerusalem, Iran).
But in these manoeuvres, the Obama campaign is applying conventional electoral wisdom to a candidate whose very appeal to voters is based on being unconventional.
So it is that the latest polls from Newsweek and Rasmussen show Obama's lead evaporating at precisely the same moment people perceive him to be less liberal and more centrist. This, and the disappointing fundraising figures should come as no surprise: he is undermining the very premise of his campaign.
He was winning over independents and inspiring the young, not by showing that he shared their views on abortion or trade, but by offering them an end to the "old politics" of political expediency.
As he said on Super Tuesday, "I want to speak directly to all those Americans who have yet to join this movement but still hunger for change. They know it in their gut. They know we can do better than we're doing. They know that we can take our politics to a higher level. But they're afraid. They've been taught to be cynical."
A candidacy built on the desire to "take our politics to a higher level" cannot afford to let its supporters get too cynical. Obama needs to have the courage of his conviction that America is "ready to believe."
Now, John McCain is probably too old, and angry, and bald, and Republican to win this election, whatever Barack Obama does. His positions on abortion, Iraq, and health care alone should make even the most reluctant Democrats get out and vote. The unpopularity of Bush, alongside rising gas and grocery prices, and the decimation of the housing market should hand the Democrats the White House.
But the Obama campaign cannot afford to lose its way.
Because if the Democrats are going to win in November, Obama needs to maintain the "enthusiasm gap" we read so much about. Without public finance, he is also going to need the continued financial support of his small donors. And faced with the possibility of losing some traditional swing states, he is going to need record turn out among young voters and African Americans in states that have recently trended Republican.
Every shift of position makes those things more difficult to achieve for a politician who has based his candidacy on the idea that Americans "want to believe again."