This paper considers a climate policy architecture that would be conducive to wide participation and successful compliance. Compliance in particular is an aspect of climate policy that has been under-specified in current proposals for an architecture for climate policy. Although admittedly a successful regime would have to satisfy a number of criteria, including environmental goals, dynamic efficiency and cost-effectiveness, any agreement would have to be implemented and enforced. The focus here is both on how to construct a regime that is environmentally effective, and on how to reduce problems of compliance and leakage. Other criteria will be considered in the proposal, such as cost-effectiveness and how to facilitate the negotiation process, but the primary focus will be on participation and compliance. The main argument is that a climate agreement based on both emissions targets and policies and measures is the most conducive to maximum participation and a successful compliance mechanism.