A modest target for the stabilization and subsequent reduction of greenhouse-gas emissions. Legal authority for the Environmental Protection Agency to regulate such emissions. Establishment of some of the rules needed to foster a free and open market for emissions trading. Some fine-tuning of the federal government's climate-change research programme.

The central points of the American Investments for Reduction of Emissions Act of 2003, which was introduced last week by senators John McCain (Republican, Arizona) and Joe Lieberman (Democrat, Connecticut), would be regarded by many as a perfectly reasonable set of precautions against the likely dangers of global climate change.

Will the US Senate enact the measure? Not a chance. After due consideration at a hearing of the commerce committee on 8 January, the measure is going nowhere fast in the Senate. The Bush administration is dismissive of it and the House of Representatives is uninterested.

Two of Bush's most formidable opponents — McCain inside the Republican party, Lieberman outside it — know this well enough. Their real intention is not to pass a bill. It is to send a signal that the president's nonchalant disregard of this issue will one day come back to haunt him (see page 202).

McCain picked up his own interest in the issue on the campaign trail for the last presidential election. In the cold school halls of Iowa and New Hampshire, the environmentally hawkish senator gained the impression that young people in America feel betrayed by Washington's failure to engage with the problem of global warming. He changed tack on the issue, and now joins long-time environmentalist Lieberman in addressing it.

But the two men are also sending out a message to the world at large: that Bush doesn't speak for America on climate change. Their concerns are quietly shared by many Americans — in fact by most, according to polls. And around America, two-thirds of states are taking measures that will encourage a reduction in greenhouse-gas emissions.

Meanwhile, elsewhere in the world, ratification of the Kyoto Protocol is proceeding far more vigorously than its supporters anticipated – partly on account of the characteristic petulance with which Bush saw fit to withdraw from it. Instead of using his exit as an excuse to renege on the agreement, as they might well have done, close allies with conservative governments have confirmed their plans to ratify. Last month, indeed, Canada became the hundredth nation to do so. Russia is likely to come on board too, ensuring that participation reaches the threshold to bring the treaty into force without US participation.

In the long run, people who have a sense of the appropriate role of the United States in the world — people such as McCain and Lieberman — will regain influence. Something akin to the bill that the dynamic duo introduced last week will one day pass into law. While waiting for that day, the rest of the world must confront the challenge of global warming on its own.