Final answer:
The Populist Party supported a graduated income tax to address economic inequality and benefit the working class and farmers.
Step-by-step explanation:
The Populist Party supported the idea of a graduated income tax because they believed it would address economic inequality and benefit the working class and farmers.
By implementing a progressive tax system, where the rich pay a higher percentage of their income in taxes, the Populists aimed to redistribute wealth and provide economic relief to those who earned less.
This policy proposal was opposed by the robber barons and industrialists because it would require them to pay a larger share of their income in taxes.