Heather Cox Richardson: I know people are on edge, and there is maybe one last thing I can offer before this election. Every place I stopped, worried people asked me how I have maintained a sense of hope through the past fraught years. The answer -- inevitably for me, I suppose -- is in our history. If you had been alive in 1853, you would have thought the elite enslavers had become America's rulers. They were only a small minority of the U.S. population, but by controlling the Democratic Party, they had managed to take control of the Senate, the White House, and the Supreme Court.