Spot the clues in the battle of the veeps

Out of America: Vice-presidential debates have a chequered history, but sometimes they can be a springboard to the top job

Time to shine: Paul Ryan, right, with Mitt Romney on the campaign trail in Virginia last week (AFP)

And now to the veeps, one actual, one would-be. On Thursday night Paul Ryan and Joe Biden face off for their single vice-presidential debate, and it should be fun. Both are engaging characters; both enjoy a joke. Biden has an endearing habit of putting his foot in his mouth. Ryan is prone to statistical whoppers as he pursues the partisan fight, but his choirboy looks and disarmingly friendly style make it easy to forgive him. But what makes their confrontation especially interesting is that, suddenly, the stakes are higher.

Normally, vice-presidential debates are part of the campaign under-card. Yes, they've produced the odd great line – none better than Lloyd Bentsen's withering "Senator, you're no Jack Kennedy" put-down of Dan Quayle in 1988, which actually had you feeling sorry for Quayle. Bentsen won at a canter, but his debating skills didn't prevent Michael Dukakis from being soundly beaten by George H W Bush in the election.

But Barack Obama's dismal performance in his first debate with Mitt Romney, just when it seemed he was cruising to re-election, may have changed the trajectory of this race. The supposedly hopeless Romney showed he wasn't so hopeless after all, and Republicans who had virtually given up on their man are now galvanised, with a genuine belief that he can win.

On Thursday afternoon I went down in Fisherville, real God-and-guns country in deepest Republican Virginia, to attend Romney's first post-debate rally. The atmosphere was positively festive, transformed by their man's blow-out win over Obama the night before. The grass-roots activists will now be more active on behalf of the cause than ever, and big party donors, who might have found better things to do than bankroll a loser, will keep the money flowing in.

The President did catch a huge break the next day, with the news that the unemployment picture had improved in September, suggesting that his policies are working, albeit slowly. And not only the labour market figures: the most recent data for consumer confidence and the housing market, not to mention a gradual rise in stock prices, also point to an economy that is on the mend.

Best for all for Team Obama, the jobless rate has fallen to 7.8 per cent, the lowest since he took office. No longer will we professional sifters of tea-leaves quite so often be reminding him that no incumbent since FDR has won a second term when the jobless rate is 8 per cent or more. Even so, the horse race is probably tightening, and Joe will have to be careful. A bad goof on Thursday may not be as inconsequential as usual.

In one notable respect, however, the Ryan/Biden match-up does fit a familiar pattern, of the young pup against the grizzled veteran. Nervous rookie Senator Quayle vs suave Democratic grandee Bentsen is obviously one example. Another is the 2004 debate between Dick Cheney, in and around the highest levels of government since the days of Gerald Ford, and the coltish, shallow John Edwards. Edwards's career may have ended in ignominy, but the vice-presidential nomination was a stepping stone to his second presidential bid in 2008.

And that year's vice-presidential debate turned out to be another young/old contest, pitting Biden, veteran of a couple of presidential runs and any number of Senate committee chairmanships, against the ineffable Sarah Palin.

In fact, her much awaited debate with Biden turned out to be a bust, a low-key bore draw. So anxious was he to avoid seeming condescending towards the young and terrifyingly world-ignorant Alaska governor that the debate passed off without memorable incident. With Ryan the opponent, one suspects things will be very different.

As a foreign policy expert, Biden will highlight the lack of experience in that field not only of Ryan ("Overseas, where I come from, means Lake Superior," the Wisconsin native once quipped) but of Romney himself. (See "July trip: London Olympics and Israel".) In return, though, Ryan will pummel the Obama administration's record on the economy. Joe will have to keep his guard up.

One thing, however, is certain. Paul Ryan will be with us for a while. A couple of months ago, just after he was chosen as Romney's running mate, Nate Silver made a statistical examination of his prospects, in his ever-informative FiveThirtyEight blog in The New York Times. It confirmed what one long suspected: that the best short cut to the Oval Office is via the vice-presidency. Mere nomination guarantees that priceless asset for the future: name recognition. John McCain's shock choice of Palin turned an unknown figure from a US political backwater into a national figure, to the point that conservatives begged her to get into the 2012 race. She said no – and probably very wisely – but only after flirting with the notion for months.

Victory obviously improves your career prospects even more. Of the 47 men who have been vice-president, no fewer than 14 – almost one in three – have later become president. As for Ryan, if he's on the winning ticket next month, there's an 80 per cent chance he'll run for president one day, and a 50 per cent chance he'll win the nomination.

Biden too cannot entirely be ruled out; indeed, he is said to be seriously contemplating a third White House run. But his days in national politics are surely nearing an end. If he ran and won in 2016, he would be 74 when sworn in, five years older even than Ronald Reagan was when he took office.

Ryan, though, is not just a young pup; he's a personable young pup, liked and respected at every level of his party. Barring a Republican defeat for the ages in November, he'll surely be a figure in national politics for many years. It's worth remembering too that when the Republican ticket of Warren Harding and Calvin Coolidge won by a landslide in 1920, the losing Democratic vice-presidential candidate was a certain former assistant secretary of the navy named Franklin Delano Roosevelt. Look what happened to him.