Like most members of President Obama's climate team, David Sandalow was one of President Bill Clinton's negotiators in Kyoto. And he carries an indelible lesson from the experience of signing off on the international climate pact there 12 years ago: 'Only agree abroad to what you can implement at home.' He had been elated at the deal by more than 180 nations in December 1997. But within months, a television ad appeared, decrying the agreement for not including developing nations such as China and India. 'It's not global and it won't work,' said the ad, which was sponsored by business groups including the American Association of Automobile Manufacturers and the American Petroleum Institute. It captured the growing discontent in the United States over the Clinton administration's signing off on a package that did not force similar cuts by major developing countries. That political backlash is one of several reasons why any deal struck two months from now in Copenhagen will at best signal the start of a new global approach to tackling climate change, rather than its successful conclusion. Kyoto's legacy -- including the decision to exclude major developing countries from the agreement, the failure of the United States to ratify it and the fact that many of its signatories have missed their emissions targets -- continues to dominate U.N. talks aimed at curbing the world's greenhouse gas output. It has made the United States more cautious about defining specific reductions, made other industrialized nations skeptical of the U.S. commitment and made developing countries more insistent on getting money from rich nations to address their problems. 'If we have any kind of international agreement in Copenhagen, there will have to be some accommodation of American political realities, but you have to meet a number of political realities on the other side,' said Melinda Kimble, senior vice president of the U.N. Foundation and a lead negotiator for the State Department when Kyoto was forged. These realities have made it harder for most of the key countries, whose representatives have been meeting in Bangkok, to reach an agreement by December, especially one that involves a massive shift of their nation's economic trajectories for the sake of a long-term reward. Even the Japanese have proposed abandoning the Kyoto agreement for a completely new structure. 'The Kyoto Protocol is a very historic protocol,' said Kenichi Kobayashi, who directs the Japanese Ministry of Foreign Affairs' climate change division. 'But now the situation has greatly changed in the last 10 years.' The biggest change is that developing countries such as China, India and Brazil -- none of whom are bound to specific climate targets under Kyoto, and continue to say they will not embrace them as part of an international treaty -- are much bigger carbon emitters than they used to be. China has surpassed the United States as the world's largest emitter, according to the International Energy Agency, with the two nations accounting for about 40 percent of the world's greenhouse gas emissions. The agency said that 97 percent of the rise in energy-related carbon dioxide emissions will come from developing nations by 2030. That makes centrist Democrats such as Sen. Evan Bayh, D-Ind., hesitate at the idea of backing mandatory curbs on U.S. greenhouse gas emissions. 'I could not ask the American people to sacrifice and not solve the problem of global warming because the developing world was not participating,' he said in an interview. But Jairam Ramesh, India's minister of state for Environment and Forests, told reporters Friday that America's near-term climate targets remain too modest. 'The stalemate in negotiations has not been caused by China and India,' Ramesh said. 'The make-or-break issue is emissions cuts. If there's no agreement on that, there's no agreement in Copenhagen.' Todd Stern, the U.S. special envoy for climate change, said he is focused on achieving 'the art of the possible. ... The task here is to get a deal consistent with those (constraints), which pushes us in the right direction.' In some ways the political climate has loosened the Obama's administration's constraints in recent months. Major U.S. companies such as Wal-Mart, General Electric and even utilities such as American Electric Power now back a federal cap on greenhouse gases, and the combination of the House-passed climate bill and legislation introduced last week by Sens. John Kerry, D-Mass., and Barbara Boxer, D-Calif., suggest that the president could meet his much-publicized goal of reducing the nation's emissions to their 1990 levels by 2020. Several environmentalists say U.S. negotiators have been too hesitant to use provisions in the House bill -- such as its emissions targets and funding to help poor countries preserve their forests and cope with climate effects -- to lay the groundwork for a global deal. 'The ghost of Kyoto hangs over the U.S. more than it does over most nations,' said Ned Helme, who heads the Center for Clean Air Policy. 'I think we could be a bit bolder now because we have a good story to tell internationally.' But on Friday, Obama's top domestic climate adviser, Carol Browner, said it was 'not likely' that a final bill would be signed by the president before Copenhagen. Stern is unwilling to codify targets internationally that the United States has yet to adopt. 'It's very difficult to do that right now if you have your eye on the prize, which is getting a good piece of legislation signed into law by the president,' said Stern, who was in Kyoto as a White House staffer 12 years ago. Instead U.S. negotiators, as well as ones like India's Ramesh, are exploring whether the world's major emitters could forge a pact that encompasses nationally binding goals and is subject -- at least to some extent -- to international review. James Connaughton, who chaired President Bush's Council on Environmental Quality, said the outcome in Copenhagen could resemble what Bush and his top deputies had sought for years. 'What all major economies realized this time around is that they need to establish a domestic consensus on an agreed level of effort as a stronger basis for the commitments they make internationally, and as a catalyst for international cooperation,' Connaughton said. 