1. Plan of the Volume; 2. The Rise of Environmentalism in the United States; 3. The Growing Party Divide on Environmentalism in Theoretical Context; 4. U.S. Environmental Politics in Comparative Perspective; 5. Charting the Partisan Divide on the Environment; 6. How Environmentalism Has Changed; 7. Environmentalism and the Politics of Party Coalitions; 8. Prospects for Change; 9. Conclusion.