The document discusses the history and evolution of federalism in the United States over several periods: 1. Dual federalism from 1787-1868 established a limited national government with states retaining most power. 2. Cooperative federalism from 1938-1964 saw increased federal regulation during the Great Depression and New Deal era. 3. Centralized federalism from 1964-1980 expanded further under programs like the Great Society and increased federal grants to states. 4. New federalism since 1980 has aimed to devolve more power back to state governments under Reagan and through Supreme Court cases limiting federal authority.