With just over two weeks to go, it is down to the ground war for Obama and Romney: knocking doors, making phone calls, and persuading every last voter to the polls.
You might call it ironic. After years of sophisticated political planning, after hundreds of millions of dollars to fill the airwaves with an incessent cacophony of political ads, the election is down to this: knocking on doors, making phone calls, handing out leaflets in the street.
For with most major polls pitting Obama and Romney in a virtual dead heat, what matters now, is getting out every precious vote. Obama's campaign manager Jim Messina summed it up: "What we've got to do is two things, and two things only: persuade the undecided, and turn our voters out."
And in a race where you could practically count the number of undecided voters on the fingers of one hand, turnout coud well hold the key to victory in November.
What we've got to do is two things, and two things only: persuade the undecided, and turn our voters out. Jim Messina, Obama campaign manager
Despite the panic over sliding polls, there is reason for some quiet confidence in Democratic ranks over the power of Obama's formidable political machine, that has been four years in the building.
According to Messina, at the time of the Democratic National Convention, the campaign and its supporters had made 43 million phone calls and registered more than a million voters, more than the already high numbers registered during the last election.
A nationwide network of field offices have been working away for months, sometimes years: in many cases, teams have been in place since 2008. Along with thousands of paid, full time staffers, hundreds of thousands of volunteers have been staffing the phones and pounding the streets, plugged right into their own neighbourhoods, where local knowledge and influence is what counts.
For obvious reasons, rescources are concentrated in the swing states: volunteers are sent there from places where the race isn't so close, even from overseas. They sleep on floors, in spare rooms, wherever they can find a place. Some have saved up precious holiday time for years to join the cause.
It is all about targets, or rather, micro-targets: reaching key voters with niche messages, using all the sophisticated technology they can get their hands on. Volunteers do not just make random phone calls any more, running the risk of wrong numbers or outdated contacts.
Precinct teams have spent months honing and perfecting lists of likely voters: while the millions of dollars which has been quietly spent on voter reasearch means there's a whole host of other data, from spending habits to what cars people drive. Want to spot a liberal? Look for the Prius, or the Subaru Outback.
In Florida, for example, Team Obama has more than 100 field offices - more than twice as many as Romney's campaign. You can find volunteers outside bodegas, African-American hairdressers, anywhere potential supporters might be. Even the tiniest advantage could make all the difference.
In Ohio, which could well hold the key to an Obama victory, the base is growing less than enthusiastic. The polls are narrowing. Here, amid a relentless barrage of advertising, the battle is being fought by ordinary people, door-to-door, street by street.
As Politico's Glenn Thrush warned: "If Obama can't close that gap by mobilising his base of black, Latino, young and highly educated voters, he's toast - and Chicago knows it."
Four years ago, the power of that Chicago-run machine swept all before it. John McCain's woeful efforts to get out the Republican vote were left trailing. This time, though, the GOP has upped its game.
Now they are boasting 108,000 volunteers, and say they have knocked on 7.5 million doors and made 40 million "voter contacts". There is some decent technology at play too, helping to create those crucial voter lists in time for election day, and urge early voters to cast their ballots.
One optimistic Romney aide was heard telling reporters they were confident not just of victory, but an overwhelming one: 305 electoral votes.
The likely voter
But perhaps the winning margin will not depend on the mythical "undecided voter", but the equally nebulous "likely voter". Which side will prove most capable of overcoming latent apathy, and generating sufficient enthusiasm to propel their core supporters to the polls?
When Joe Biden spoke to a room of volunteers in Florida this week, according to reporters at the event, he told them they were the epicentre of the epicentre. "Florida, you guys produce. We win Florida, this is all history, man."
The Sunshine State now seems to be outside Obama's reach, given all the Romney momentum. But that does not mean the battle is over, and all the number crunchers out there are busy constructing various paths to victory through the complex electoral map. If not Florida, then Ohio, Nevada, Wisconsin... the options are seemingly endless.
With just over two weeks to go, it is truly down to this. A room, and thousands like it, festooned with papers and banners and humming with computer screens on overdrive. Half-eaten doughnuts and empty soda cans, and overcaffeinated volunteers hunched over phone banks, stuffing envelopes, downloading data.
It just goes to show. You can spend all you like on the media wars, but if you cannot get those voting slips into the ballot boxes, it is all just so much passion spent.
Felicity Spector writes about US politics for Channel 4 News