THE YOUTH vote was supposed to win it for John Kerry, so when he was defeated by George W Bush in 2004 many Democrats blamed young people for failing to show up in greater numbers. Despite Rock The Vote's blend of live music and political activism, and an appeal by hip-hop superstars to Vote Or Die, the percentage of voters aged 18 to 29 remained the same as it had been four years earlier, at just 17%.
The late Hunter S Thompson was not surprised. "We rocked the vote all right," he said. "Those little bastards betrayed us again." In all his time covering politics, starting with George McGovern's failed 1972 attempt to surf a wave of youthful enthusiasm to the White House, Thompson had learned never to trust students at the ballot box.
Democrats seeking reasons to be cautious have fastened on to this most unreliable demographic. Nothing can be taken for granted, least of all first-time voters, but it is worth noting that Thompson, normally such an acute political observer, was wrong. Youth turnout did increase last time, by more than four million votes. The percentage was unchanged because participation swelled across the board. They just didn't support Kerry as much as expected: 54% of their votes wasn't enough because he lost every other age group.
This election will be different. Firstly, in contrast to Europe, America is getting younger - a trend driven by Latino families who have children early and often. There are millions more potential voters in the youngest age bracket than ever before, and they are more diverse than previous generations, at around 60% white. They also don't appear in polls, because the screening for "likely voters" often eliminates first-timers. Around a third of young people also rely exclusively on a mobile phone, putting them out of reach of conventional surveys.
Secondly, a look at historic levels of engagement shows students are more politically motivated than they have been for decades. Turnout has continued to increase since 2004. Many analysts credit Senator Jim Webb's victory in Virginia two years ago to a surge in college towns. The proportion of 20-something voters rose from 18% to 32% - a difference of 128,000 votes in a state where the eventual margin of victory was just 8000.
This year's Democratic primaries were even more eye-catching. Including the caucus states, almost five million young people took part, up from a little over one million last time around. Fewer than two million voted in the Republican primaries, while Democratic youth turnout tripled in the key swing state of Florida, although it's important to note that it was starting from a low baseline, rising from a pathetic 4% of eligible voters to 13%.
Thirdly, Barack Obama is running the slickest, most technologically aware campaign ever. Advertising Age recently awarded Marketer Of The Year to his team, observing that "across multiple media platforms, they've managed to drive a potent, single-minded design and messaging coherence that should shame many national brands".
The advert pointing out that McCain "admits he still doesn't know how to use a computer, can't send an email" was a rare tone-deaf moment, more likely to lose older voters than gain teenagers, but the candidates' competence is not the point. It is the ability to organise on new media platforms that counts and the Republicans have been left behind, just as Hillary Clinton was in the primaries.
On Facebook, Obama has 2.2 million supporters, four times as many as McCain. Even though half these "friends" are overseas, this is a significant advantage among a demographic group that is difficult to reach with traditional television advertising. Memos are written in shorter paragraphs, with fewer detail, for shorter attention spans. On his MySpace page, a video tells children how to Convince Your Parents to Vote for Obama.
On Friday, a friend calling himself Maskins posted "u have my support i bleave u will pull this country out of the downward sprial we r currently in".
Say what you like about declining standards of literacy, Maskins is 18 and lives in Pennsylvania, a potentially decisive battleground. If the campaign can use MySpace to get him to the polls, their man is one vote closer to the presidency. Obama's mood is described as "Hopeful" next to a smiley yellow face.
McCain's team have learned a lot since the primaries, when they all but ignored social networking sites. The latest addition to his Facebook page is a game called Pork Invaders, in which players fire presidential vetos at space pigs representing wasteful government spending. The scoreboard records "tax dollars saved (in millions)".
On the day of Obama's acceptance speech in Denver, his Colorado campaign chairman, Ray Rivera, asked the crowd to send text messages to their friends. Stars flashed on a map on the stadium scoreboard each time a text was sent. This was part of an aggressive registration drive that has allied new technology to old-fashioned canvassing. Nine million new voters have signed up this year: where registration is recorded by party, there are four times as many Democrats as Republicans in the class of 2008.
Bill Clinton's strategist James Carville once said: "Show me a candidate who depends on the youth vote and I'll show you a loser." Obama will surely demolish McCain among younger voters (a Harvard University poll last week had him leading 56% to 30%) but he no longer depends on them.
With the economic crisis and McCain's faltering campaign driving undecided voters away from the Republicans, Obama now leads the coalition of students, African-Americans, union households, college-educated liberals and low-income families the Democrats have tried and failed to unite so many times. It will take a momentous October surprise to stop him. It's just a shame Hunter S Thompson is not here to see it.