Even Tony Blair occasionally gets something right. His observation this week about climate change - that the problem seems so huge people don't know what they can do about it - was one such occasion. In the midst of our second blisteringly hot summer in only four years, the impact of humanity's profligate attitude to the environment has become hard to ignore.
You may be able to brush aside warnings about holes in the ozone layer or melting polar ice caps, but budget airlines will fly you to parts of the Spanish coastline where changing sea temperatures are putting swimmers at risk of nasty jellyfish stings. Even if you choose not to holiday abroad, your garden is probably dying before your eyes, and you may, like me, be taking anti-histamines to deal with unseasonal allergies.
But this is a subject where the gap between knowledge and action is wide, not least, as the Prime Minister suggested, because individuals feel helpless. Two days ago, he sought to address that problem by floating the idea of carbon audits for individual homes to give each of us an idea of how much we're contributing to environmental pollution. He also said he was trying to do his bit by installing low-energy light bulbs and turning down the thermostats by one degree in Downing Street.
Such gestures are easy to mock, especially as government ministers chose the very same moment to distance themselves from MPs' proposals to tackle climate change through steep rises in the cost of air travel and car taxes. He's not quite fiddling while Rome burns, but a vision of the Prime Minister up a ladder at No 10, while Cherie hands up one of those funny-shaped bulbs, doesn't fill me with confidence that he's getting to grips with the threat of desertification.
Only last week, in Los Angeles, Blair described combating climate change as a "vast moral cause", pointing out that its effects would fall disproportionately on the world's poor. The logic of his speech was that urgent measures are needed, yet this week his Transport minister, Stephen Ladyman - presumably with Blair's blessing - responded lukewarmly to proposals from the House of Commons environmental audit committee.
The MPs want a new car tax-band of up to £1,800 a year for gas-guzzling vehicles, but Ladyman said their owners already paid "substantial additional costs" in fuel and duty and weren't put off; drivers of SUVs are apparently too rich to be deterred by financial penalties. To be fair, Ladyman was equally unenthusiastic about increasing the tax on air travel, this time on the grounds that it would hurt the poor, who would no longer be able to afford foreign holidays.
I'm not sure that's quite what Blair meant last week, but it is at least even-handed. Yet if the Government has given up on trying to change the habits of the affluent, and doesn't want to change the habits of the poor, it isn't left with much room for manoeuvre. I suspect that the Prime Minister's enthusiasm for carbon audits may diminish if it turns out that householders discover that they need to make costly alterations to their homes to reduce emissions.
There is a problem here which leading politicians are reluctant to address. The Blair Government is often accused of being managerial, lacking the vision and confidence to bring about change, and nowhere is this more evident than in its approach to the environment. Not only do ministers appear to believe they can't change human behaviour; they are afraid even to try, for a very simple reason.
I have no doubt that Blair, unlike his buddy George Bush, understands the seriousness of the threat posed by climate change. But when ministers in his Government look at drivers of SUVs or the lengthy queues at the easyJet check-in desk at Stansted, they don't see people inadvertently or otherwise destroying the environment; they see voters. They see people who are already fed up with the Prime Minister and who may well be eyeing that nice Mr Cameron, thinking it's time for a change. The last thing ministers want is to hand them another reason to get cross with the Government.
Tell young men that the days of cheap stag weekends in Barcelona are over and they'll switch to the other guy, or so the conventional wisdom has it. It's a hugely pessimistic view of human nature and politics, predicated on the notion that politicians actually have very little power or influence in modern democracies. The Blairites have subscribed to some version of this analysis from the beginning, gradually moving towards an authoritarian agenda - Asbos, ID cards, exclusion areas for teenagers - as their inability to influence behaviour became an electoral liability.
It's a view they share with leading Democrats. Now that Al Gore is no longer, nominally at least, second most powerful man in the world, he has become a mesmerising advocate for action to halt climate change. Meanwhile his former boss has set up the Clinton Climate Change Initiative, declaring in the presence of Tony Blair last week that "the fate of the planet that our children and grandchildren will inherit is in our hands and it is our responsibility to do something about this crisis". Stirring stuff, except that after eight years of leadership from Clinton and Gore, Americans were still driving around in huge cars and paying risible prices for petrol.
The implication is that only elder statesmen (and women) are in a position to tell the truth about global warming and do something about it, in the shape of the limited initiatives available to well-placed private citizens. It assumes that democracies are doomed to become the possession of competing interest groups, transnational corporations on the one hand and consumers on the other, all acting out of narrow self-interest.
What this ignores is the power of advocacy, when political leaders stop being managers and speak from the heart. This may not be an easy prescription for a party which, under Blair's leadership, seems to have some difficulty locating that organ; in a worrying sign for Labour activists, the committee whose innovative proposals the Government has just sidelined is chaired by a Conservative MP, Tim Yeo.
But it may point the way forward. Cross-party consensus on measures to tackle climate change would remove the fear of punishment at the ballot box, which makes too many MPs play down a threat bigger than global terrorism. Sometimes people need to be told the truth, not in the moralising tone favoured by the Prime Minister, but in terms that make them question the wisdom and impact of their choices. If we live in democracies where political leaders dare to be radical only when they leave office, the planet will pay a heavy price for their short-term thinking.