President George Bush's bid to stop international action to combat global warming faces failure this weekend, as he is left more isolated than ever before both at home and abroad.
Russia's President Vladimir Putin - who will effectively decide whether the Kyoto Protocol stands or falls - announced on Friday that his country would "rapidly move towards ratification" in the wake of a complex deal with the European Union.
One British source close to negotiating the deal said yesterday that the announcement was "more than I had dared to hope". Another said he thought it increased the likelihood of the treaty coming into effect "from less that 50 per cent to about 90 per cent".
Mr Bush is also coming under increasing pressure at home from industry, Congress and Republican governors. The Senate, unanimously opposed to the Kyoto Protocol seven years ago, is expected to pass a resolution backing strong action on global warming next year, whoever wins the US presidential election.
Mr Putin's announcement, by far the strongest statement of support for the treaty that he has yet made, immediately followed the EU's agreement, at a Moscow summit, to drop objections to Russia joining the World Trade Organisation.
Under the protocol's complex terms, Russia's support is all that is needed to bring it into effect. But over recent months, President Putin has been predicted to reject it, dooming it to failure.
Mr Putin's economic adviser, Andrei Illarionov, has been increasingly strident in his condemnations; he described it last month as an "economic Auschwitz".
Last week, a report by experts from the Russian Academy of Sciences, led by Professor Yuri Israel, another prominent critic, told the President that ratifying the treaty would damage the country's economy. And on the eve of the summit senior Russian government sources were insisting that Kyoto would not be on the agenda.
Yet, almost unnoticed, Mr Putin has been inching in the opposite direction. In a meeting with Romano Prodi, the President of the European Commission, last month, he privately distanced himself from Mr Illarionov. In another, with the Italian Prime Minister, Silvio Berlusconi, he discreetly intimated that Russia might soon endorse the treaty.
Concern about the US's policies in Iraq has played a part in the shift, as has a desire for warmer relations with the EU, now Russia's neighbour following the accession of Eastern European countries this month. But the crucial factor has been gas prices. Russians pay only a fifth as much for the fuel as its overseas customers; until now the EU has insisted that prices must be equalised, at the risk of severe damage to the economy, if Russia is to be allowed to join the WTO.
Friday's deal, brokered by the EU trade commissioner, Pascal Lamy, will let Russia join the organisation so long as it doubles the domestic price. Mr Putin, who has been using Kyoto as a bargaining counter, can present this at home as an important political victory. It will also provide a boost to the growing support in the US for action on global warming. Opinion polls show that 70-80 per cent of Americans want their government to take the lead on combating climate change.
Surprisingly, Mr Bush is under pressure from the industry responsible for much of the pollution: electric power companies owning nearly two-fifths of US generating capacity have endorsed legislation that would compulsorily limit their emissions of carbon dioxide, the main global-warming gas. There are even indications that ExxonMobil, the main industry cheerleader for the President's position, is beginning to change its stance.
Three key Republican-governed states - California, New York and Massachusetts - have parted company with the President and moved to take aggressive measures to reduce emissions. Both houses of Congress have called on the Bush administration to return to the negotiating table.
The US will not join Kyoto as it stands. But a deal looks more possible this weekend than at any time since Mr Bush took office.