The 1990 Canadian Green Plan is useful as a case study in examining the five key political and policy imperatives essential in green plan formation, defined as systematic efforts by western governments to transform their environmental policy approaches from a remedial clean-up approach after pollution has occurred to a preventive approach intended to support sustainable development. The five political and policy imperatives are prime ministerial leadership; sustained ministerial and bureaucratic coordination and leadership; strategic support by both environmental nongovernmental organisations (ENGOs) and business interests; a suitable conceptual framework for articulating and communicating the meaning of sustainable development in a world of mass-media-driven politics; and the right mix of policy instruments.