Policy designers are actively searching for more durable climate policy designs to deliver deep decarbonisation. In Chapter 1, we noted that the existing distribution of resources and actor preferences in this area means that durable policies have proven immensely difficult to design in the past. Many difficult design choices and dilemmas will need to be confronted to ensure that future policies are more durable and more effective. These choices relate to the packaging together of various internal elements to produce an overall design that generates and is in turn sustained by positive policy feedback.