I did not expect Donald Trump to win the 2016 election, and like many, many other political professionals, I was egregiously wrong. After listening to what a lot of diehard Trump fans had to say, I took two big lessons away from being that wrong. The first is that I’m not Nostradamus, and I shouldn’t be in the business of definitively saying one candidate will win or lose a race. Hopefully, a lot of us learned that lesson in 2016. The other is that unfortunately, a large number of conservative Americans have given up on people like me, on people...