International negotiations are focused on developing a climate policy framework for the post-2012 period, when the Kyoto Protocol's first commitment period will have ended. In addition to negotiations under the United Nations Framework Convention on Climate Change (UNFCCC), other intergovernmental outlets, including the G20 and the Major Economies Forum, are trying to reach common ground among the world's major emitters of greenhouse gases. To date, these efforts have not produced a politically, economically, and environmentally viable structure for a future climate agreement. An effective, but more flexible and politically palatable approach could be an international agreement on a "portfolio of domestic commitments." Under such an agreement, nations would agree to honor commitments to greenhouse gas emission reductions laid out in their own domestic laws and regulations. A portfolio of commitments may emerge from a global meeting such as the UNFCCC Conference of the Parties, or a smaller number of major economies could negotiate an agreement among themselves, and then invite other countries to join. Despite the obvious differences between such a system and the conventional "targets and timetables" in the Kyoto Protocol, negotiators should not dismiss this new approach out of hand. There are several ways to construct a portfolio of domestic commitments, and negotiators have numerous levers available to tailor an agreement to meet their political, economic, and environmental goals. This Viewpoint outlines some basic features of a portfolio approach, highlights a few major issues and concerns, and discusses the potential feasibility of this approach.