Social movements take shape in relation to the kind of state they face, while, over time, states are transformed by the movements they both incorporate and resist. Social movements are central to democracy and democratization. This book examines the interaction between states and environmentalism, emblematic of contemporary social movements. The analysis covers the entire sweep of the modern environmental era that begins in the 1970s, emphasizing the comparative history of four countries: the US, UK, Germany, and Norway, each of which captures a particular kind of interest representation. Interest groups, parties, mass mobilizations, protest businesses, and oppositional public spheres vary in their weight and significance across the four countries. The book explains why the US was an environmental pioneer around 1970, why it was then eclipsed by Norway, why Germany now shows the way, and why the UK has been a laggard throughout. Ecological modernization and the growing salience of environmental risks mean that environmental conservation can now emerge as a basic priority of government, growing out of entrenched economic and legitimation imperatives. The end in view is a green state, on a par with earlier transformations that produced first the liberal capitalist state and then the welfare state. Any such transformation can be envisaged only to the extent environmentalism maintains its focus as a critical social movement that confronts as well as engages the state.