As ripostes to High Court judges go, the Nobel Peace Prize is hard to better. As a vindication for a failed politician who bequeathed George W Bush and his works on the world, meanwhile, good news from Norway is no small consolation. After all, if you have had the presidency of the United States stolen from under your nose, every little helps.

Albert Arnold Gore Jr probably does not care to be remembered as the 45th vice-president of the US. It is not an office that much enhances the CV. Unless you are a Dick Cheney, pulling the strings to which Bush dances, people tend to ask what you do for a living.

In the case of Gore, the dismal answer until recently was two-fold: losing the White House after Bill Clinton had seemed to hand him victory on a plate and, vaguely, "environmental stuff".

True, he actually beat Bush in the popular vote in 2000, losing the electoral college only because of certain, shall we say, polling peculiarities. On the other hand, if you fail to carry your own state (Tennessee), sympathy is limited.

Equally, while Gore was a prime mover behind the Kyoto environment protocols, he failed to persuade the US Senate to sign up. Bush then behaved as though the climate change argument was just another liberal plot. On that reading, Gore failed to save either his career or the planet.

The latter is still in some trouble; the former, suddenly, is resurgent. Judge Michael Burton, ruling in an English propaganda- in-schools dispute this week, may have declared - for all judges are experts - that the campaigning film An Inconvenient Truth contains "nine scientific errors". Gore has an Oscar, a supportive scientific consensus - and now a Nobel with which to answer.

In any case, even before the Norwegian committee published its citation, Gore's stock was reviving. His film - based on a slideshow presentation the former vice-president had developed - revealed him in a new light.

Gone was the candidate with the eloquence of a lump of sustainable timber. Gone were the attempts to squeeze his considerable frame into the timid, self-censoring form of a presidential hopeful.

Faced with the environmental crisis, Gore spoke his mind. He seemed liberated, bold, clear and passionate. For all the world like The West Wing's Jed Bartlet (another Nobel winner, after all), the new Gore sounded like a man with ideals and answers. America likes ideals and answers. It's what is known as presidential.

On Wednesday of this week, an outfit calling itself had 136,000 signatures on a petition and a full-page advert in The New York Times begging Gore to make another run at the White House. With several hundred local groups already organising on the non-candidate's behalf, DraftGore declared: "There are times for politicians and times for heroes. America and the Earth need a hero right now. Please rise to this challenge, or you and millions of us will live forever wondering what might have been."

What they meant was that many Democrats are deeply uneasy about Hillary Clinton and her attitude towards the Iraq war. Gore, a critic of the occupation, is suddenly the voice of righteousness and - the Nobel says so - a man of peace. Eight years working for Hillary's husband have been forgotten. For that matter, long years as a standard-issue Democrat have been forgotten.

That may not be the point. Gore, still insisting that he has no intention of seeking the nomination, is proving that there is life after politics. Or, rather, he is proving that politics by other means can be as powerful as the conventional variety. Bill Clinton has his foundation; Tony Blair has his Middle East mission. But Gore, never a bosom pal of his old boss or a blood brother to the former Labour leader, has all but invented a new category of international statesman.

Good, no doubt, for him. The process of finding an American president is sterile, at best. The British equivalent, with its trimming and spinning, is little better. If the Nobel citation is anything to go by, Gore is proving that more can be achieved by extra-political means than through elected office. Arguments can be put, compromises can be discarded, and hearts and minds can, with luck, be won. All for the sake of the planet's future, if any.

Clearly, the peace prize committee, always keen on a political gesture, are impressed. Like many others, they suspect that environmental degradation will one day lead to wars as resources become scarce.

They are no doubt also aware that the next United Nations climate change conference will take place in Bali this December. By granting their honour jointly to Gore and the UN Intergovernmental Panel on Climate Change (IPCC), they endorse both a man and a cause.

Fine, so far as it goes. I am no climate change sceptic. The 3000 or so scientists involved in the IPCC had my vote several years back. Their opponents (and Judge Burton) strike me as perverse, ignorant or compromised by vested interests. The planet is in trouble. Yet that doesn't mean I am not also troubled by Al Gore, the unelected environmental superstar.

I don't mind that he has not actually achieved anything concrete as yet. Prophets should sometimes be honoured. But if Gore's recent career demonstrates anything, it is that politics, in the usual sense, has failed. He has been more effective by far as a propagandist than as a legislator. He has shown that more can be done with Hollywood celebrity than with elected office. He wins the votes of a Nobel committee after failing to win the support of his own people. I call that a little troubling.

Gore the extra-political activist is not, of himself, the problem. Many great causes have followed that route, after a fashion. But are we really to accept that a hit movie is a more legitimate tool than the work of any legislature? If even the peace prize is propaganda, the dull business of voting and law-making has been circumvented entirely.

Should you believe that climate change is a crisis of global proportions, that might not seem to matter. Perhaps it does not matter much. If Gore should succeed, if the world and a new generation begin to awaken to the challenge, I won't quibble. But what if I thought the cause was disreputable, if Gore happened to be pursuing ends I deplored, if Hollywood populism and politically motivated honours were being put in the service of a different cause?

I'm not sure how comfortable I would be with Activist Al in that situation. If I disliked the ends, I would think harder about the means. Gore is "raising awareness", "starting a debate", "putting forward the facts": all very laudable. But he is also attempting to secure political change around the world with charisma and camerawork. One word springs to mind: Bono.

We tend to confuse propaganda with falsehood. It isn't necessarily so. The best propaganda is based on solid fact. Yet, as history has shown, its methods can as easily be exploited for the sake of murderous lies. Gore, unwittingly, may have shown the way for individuals far creepier than he when they seek rehabilitation in this 21st century.

Still, we can worry about that after he has saved the planet, can't we?