In 1987 the UK satirical puppet show Spitting Image ran sketches showing the diminutive Liberal leader David Steel in the top pocket of Dr David Owen, his more glamorous and substantive 'Alliance' partner. From that position Steel would whine away in a high-pitched squeak, wetting himself or, most famously, "surging too early" when overwhelmed by Owen's cruel good looks. At its height, Spitting Image had more than 10 million viewers. The real David Steel later said the sketch cost him success at the 1987 general election. If John McCain and Sarah Palin go on to lose the US presidential election on 4 November, they might say something similar about Tina Fey and Saturday Night Live. For there are few things more dangerous to a politician's reputation than to be the butt of a good joke.

Tina Fey made her name on Saturday Night Live but had long since moved on. Her own TV series 30 Rock, itself based on life backstage at SNL, is a popular hit. But Fey was tempted back to SNL to play Palin because of her uncanny resemblance to the Alaska governor. It has blasted her into the stratosphere as the most talked-about comedian worldwide. The show's ratings are up 50% on last year. Millions have viewed the sketches on YouTube. Now SNL has confirmed that Palin will be appearing on the show in the next few weeks, possibly to play Fey in a spoof of the latter's commercials for American Express. So life and art imitate each other back and forth, culminating in an appearance that will genuinely deserve that overused epithet 'must-see TV'.

It would be easy to accuse SNL and NBC – part of the 'mainstream media' that many Republicans deride – of preaching to the choir. After all, Palin's folksy charm is easy to ridicule for a liberal, metropolitan audience. Yet in their parody of the vice-presidential debate, Joe Biden took as many hits as his opponent, skewered by jokes about his hair, his fixed grin and his hypocrisy about John McCain. ("This is a man I would take a bullet for, but he is bad at his job and mentally unstable.") But if the humour about Biden was
better, the subject was not. Palin – love her or hate her – is a star of this election. If Biden had been debating Governor Tim Pawlenty of Minnesota it would have been unlikely to make an SNL sketch let alone a global viral internet hit.

Many US commentators have drawn attention, almost with awe, to the fact that the SNL parodies have even permeated the most venerable "serious" political shows, such as Meet the Press. Few have mentioned the more obvious point that those parodies, subtle and sophisticated as they are, rely on a genuine and widespread public appreciation of politics amongst the American electorate. Sixty-nine million US viewers watched the real vice-presidential debate. Each of the acceptance speeches at the party conventions was seen by around 40 million. Barack Obama's speech on race in the wake of the Jeremiah Wright controversy had around 10 million hits on YouTube, including 1.5 million by people who watched the 40-minute speech all the way through.

Add to these one-off events the constant diet of 24/7 news and popular expert websites such as realclearpolitics.com and you have a level of engagement in the political process that almost takes the breath away. When Americans go to the polls in November, they will surely be better informed and more knowledgeable than any electorate before them. "Audiences have grown up," says Tonight Show host Jay Leno. "Now you can do a joke about Barack Obama without people seeing it as racist or one about Governor Palin without automatically being accused of sexism."

Opinion polls suggest that the image of America abroad has suffered in the last eight years. A majority say they have become disillusioned with the world's number-one power. This election – Tina Fey included – reminds us what we loved about America and Americans in the first place.

As it turns out, it's their sense of humour.

Prof Richard Aldous

is head of History & Archives at UCD