With a decisive victory in 1865 over Southern secessionists in the Civil War, the United States became a united and powerful nation with a strong national government. Reconstruction brought the end of legalized slavery plus citizenship for the former slaves, but their new-found political power was rolled back within a decade, and they became second-class citizens under a "Jim Crow" system of deeply pervasive segregation that would stand for the next 80–90 years. Politically, during the Third Party System and Fourth Party System the nation was mostly dominated by Republicans (except for two Democratic presidents). After 1900 and the assassination of President William McKinley, the Progressive Era brought political, business, and social reforms (e.g., new roles for and government expansion of education, higher status for women, a curtailment of corporate excesses, and modernization of many areas of government and society). The Progressives worked through new middle-class organizations to fight against the corruption and behind-the-scenes power of entrenched, state political party organizations and big-city "machines". They demanded—and won—women's right to vote, and the nationwide prohibition of alcohol 1920-1933.