Reaching out: Barack Obama at a campaign event in Richmond, Virginia on Tuesday. Opinion polls say he will take 60 per cent or more of votes among those aged below 30

James Carville once famously said: “Show me a candidate who depends on the youth vote and I’ll show you a loser.” Historically, Bill Clinton’s election strategist was dead right, but the dictum may not apply this year. Just as the colour of his skin could conceivably deny Barack Obama the White House, the support of those under the age of 30 could put him there with room to spare.