Final answer:
The Populist movement fundamentally changed American politics by introducing reforms focused on aiding farmers and workers, many of which were later incorporated into the platforms of the major political parties, thereby shaping the Progressive Era.
Step-by-step explanation:
The Populist movement of the 1890s marked a transformative period in American politics by bringing the struggles of farmers and the working class to the forefront and advocating for substantial economic and political reforms. The Populists proposed measures like a graduated income tax, the direct election of U.S. Senators, an eight-hour workday, loan programs, and the unlimited coinage of silver. Their influence was felt in the Progressive Era, as both the Republican and Democratic parties absorbed many Populist ideas into their platforms, emphasizing the need for reform in response to the economic challenges of the time. Although the Populist Party itself dissolved by 1900, its legacy lived on in American political culture, influencing subsequent policies and legislation.