Rob Stavins writes, at http://www.env-econ.net/stavins/Column_5.pdf:

[W]hen President Bush withdrew the United States [from Kyoto] in 2001... he missed an opportunity to propose a sound alternative, but his opposition was hardly new or unique. In 1997, Senator John Kerry joined with his Senate colleagues in... warning [against] reliance on targets for industrialized countries alone.... [T]he Kyoto Protocol is too little, too fast....

[But a] credible international approach is required... [that should have] three key elements.

First, both industrialized and developing countries must have serious responsibilities.... There needs to be a mechanism for developing countries to take on commitments once their per capita GDP has reached agreed levels. In the short run, developing nations must board the global climate agreement train, but cannot be expected to pay for their tickets. A well structured international emissions trading program, combined with targets for developing countries that become more stringent as they become wealthier, can do the job cost-effectively and fairly.

Second, long-term targets are required for this long-term problem.... [M]ore ambitious long-term targets [need to] be put in place now, to motivate needed technological change....

The third key element is to work through the market... [to] keep down costs of emissions reductions in the short term and bring them down even lower in the long term through technological change.... [T]radeable permits can reduce costs by as much as 75 percent by financing more climate-friendly development paths in poor countries while sparing rich countries the most wrenching and least politically realistic adjustments....

[T]he United States can place itself where it ought to be — in a position of international leadership — on this global issue...

Rob is, of course, making a joke. The chances are infinitesimal that the clown show headed by George W. Bush will assume an international leadership role on global warming.