FDR is a good example of an American leader who made substantive, wildly successful, left-leaning policy changes that ushered in decades of prosperity and (in part) last to this very day despite facing heavy opposition from the business elite of the time. They even tried to coup him!

At the time, the long term trends were dire for the American left. Double insulation was strong and getting stronger. Then the Great Depression hit. Around the world, populists and radicals were elected to office, and one way or another they changed things. In America, we managed our reform process without trying to conquer the world and without starving millions. Not Hitler, not Stalin. Roosevelt. I think that's a worthy goal to aim for again this time around.