Momentum may be building for federal climate change policy in the United States. Assuming this leads to mandatory greenhouse gas regulations, the door will be open for the United States to constructively re-engage other countries concerning an international climate regime. Such a regime will need to recognize that binding international limits are unlikely to attract U.S. participation and, therefore, will require a different approach than the Kyoto Protocol. In particular, a future regime will need to accommodate and encourage, rather than force or constrain, domestic actions to focus more narrowly on major economies and emitting nations, to balance mitigation and technology objectives, and to engage developing countries on as many levels as possible. In place of a heavy emphasis on negotiating commitments in advance, there likely will need to be greater emphasis on evaluating actions in retrospect. Such an approach not only matches recent trends in the United States but arguably follows from broader experience over the decade since the negotiation of the Kyoto Protocol.