I see people ask this a lot. It’s a good question, and while I’m not exactly an expert, I do think there are a few basic answers... https://twitter.com/drzackaryberger/status/1349386591790366722
First, the Great Depression was so catastrophic that it discredited both the Republican and the entire ethic of laissez faire. Unemployment officially peaked around 22% in 1932, but that really understates the devastation, because...
...it doesn’t count farmers who’d gone broke as wheat and cotton prices collapsed. About a fifth of the country worked in agriculture, and by the time FDR was in office, farm country had been in a years long slump (it was a large part of what made the depression great).
Second, there was a fear of social unrest—not so much at first among urbanites or factory workers (that actually came later, once things had begun to improve) but in rural America, where farmers were staging violent protests and threatening to string up judges to stop evictions.
Third, a lot of FDRs initial plans were aimed at—you guessed it—farmers and rural Americans, especially in the South snd West, where they were the base of the Democratic party.
One of FDR’s first priorities? Farm subsidies to curb crop overproduction...
One of FDR’s first priorities? Farm subsidies to curb crop overproduction...
Leaving the gold standard? In large part intended to raise farm prices. Public power projects like the TVA? That was electrifying farm country.
Four: A lot of the ideas FDR embraced had been floating in progressive Democratic circles for a while. Old age pensions? Federal unemployment insurance? A minimum wage? Those were sitting on the to-do list.
Likewise, stimulating the economy via public works spending was a widely accepted idea in the states, even prior to Keynes’ popularizing it. (Sen. Robert Wagner had spent years pushing hard for it under Hoover, who dabbled ineffectively).
Fifth: As the 30s wore on, radicals like Huey Long and the Townsendites created ideological space that made FDR’s proposals look a bit more moderate by comparison.
Sixth: The 1934 midterms created a huge wave of new, progressive democrats who helped him pass legislation like Social Security.
And seven: FDR was just good at politics. Not perfect. But Voters loved him, and for about 4 years his party was largely willing to follow his lead on domestic policy, at least until the conservative backlash that came to a head with court packing. Presidents matter.