Final answer:
FDR needed to convince Congress that his New Deal plan was essential to overcome the Great Depression by demonstrating its ability to restore public confidence in the economy and provide economic relief and reform. Congressional support was crucial for passing the New Deal legislation, as it implied major changes to the federal government's role in economic recovery.
Step-by-step explanation:
President Franklin D. Roosevelt (FDR) needed to convince Congress that his New Deal plan would work because it represented a significant shift in the federal government's role in the economy. His proposal included various economic measures designed to recover from the Great Depression, and he needed legislative approval to implement them. Congressional support was essential for the New Deal to restore public confidence in the banking system, launch work-relief programs, increase the bargaining power of industrial workers, and directly help farmers.
Understanding the economic conditions of the 1930s and the Supreme Court's initial opposition to the New Deal helps to contextualize the necessity of convincing Congress. With widespread unemployment and economic turmoil, FDR's plan addressed both immediate relief and systemic reform. Therefore, presidential persuasion was vital to overcome skepticism and demonstrate that the proposed federal action was necessary to stabilize and improve the nation's economy.