The Progressive Era in the United States was a period of reform which lasted from the 1890s to the 1920s. Responding to the changes brought about by industrialization, the Progressives advocated a wide range of economic, political, social, and moral reforms. Initially the movement was successful at local level, and then it progressed to state and gradually national. Both the reformers and their opponents were predominantly members of the middle class. Significant changes achieved at the national levels included the income tax with the Sixteenth Amendment, direct election of Senators with the Seventeenth Amendment, Prohibition with the Eighteenth Amendment, and women's suffrage through the Nineteenth Amendment to the U.S. Constitution. Muckrakers were journalists who exposed waste, corruption, and scandal in the highly influential new medium of national magazines, such as McClure's. Progressives shared a common belief in the ability of science, technology and disinterested expertise to identify problems and come up with the best solution. Progressives moved to enable the citizenry to rule more direct city and circumvent political bosses; California, Wisconsin, and Oregon took the lead. California governor Hiram Johnson established the initiative, referendum, and recall, viewing them as good influences for citizen participating against the historic influence of large corporations on state assembly. About 16 states began using primary elections. Many cities set up municipal reference bureaus to study the budgets and administrative structures of local governments. In Illinois, Governor Frank Lowden undertook a major reorganization of state government. In Wisconsin, the stronghold of Robert Lafollette, the Wisconsin Idea, used the state university as the source of ideas and expertise. Characteristics of progressivism included a favorable attitude toward urban-industrial society, belief in mankind's ability to improve the environment and conditions of life, belief in...