FOLLOWING RUSSIAN President Vladimir Putin's long-awaited signature Friday, the Kyoto Protocol on climate change will finally go into effect. Mr. Putin has not decided to ratify the treaty because his compatriots suddenly saw the light and decided to become environmentalists, although some will try to portray it that way. In fact, the Russians bargained hard, winning European endorsement for World Trade Organization membership in exchange for their signature. Moreover, Russia will gain financially from the treaty, because it is based on a requirement that signatories reduce their greenhouse gas emissions from 1990 levels. Russia's industrial output has collapsed since then, along with greenhouse gas emissions. No regulation, taxes or pollution controls are necessary.

In this sense, Russia is not alone. Britain, which has pushed hard for ratification of the treaty, also stands to gain, thanks to the country's move away from coal. China and India, which ratified it, are not, as "developing countries," required to meet any emissions targets at all. The United States, by contrast, would find compliance with the treaty extremely expensive: Meeting the targets here as well as in some other countries, such as Canada and Japan, would almost certainly reduce economic growth. Yet even advocates concede that the treaty will have virtually no effect on global warming. Its international impact is too narrow, particularly because there is no clear sanction for countries that do not meet their global obligations. For those reasons, it is hardly surprising that the Senate refused to ratify the Kyoto treaty. It makes no sense to sign a mostly symbolic treaty, to pay a huge economic cost and to get only a negligible environmental gain in return, particularly when it isn't clear that others are going to comply.

None of which is to say that the Bush administration was right to walk away from the negotiating table. The administration's abrupt abandonment of the treaty in 2001 was bad diplomacy, and it has cast a pall over transatlantic relations ever since. But there is a chance to regain some ground during further rounds of the Kyoto process that are due to take place over the next several years. Entering his second term, the president has a fresh opportunity to state clearly that America is interested in halting global warming and to advocate more equitable and possibly more unorthodox means to do so. An international effort to find alternatives to fossil fuels, for example, could ultimately prove far more beneficial than the Kyoto protocol. But that will be possible only if the president decides he cares enough about the issue, and enough about diplomacy, to remain at the table.