I think there is a world of difference between a Trump presidency with a democratic house and senate and a Republican supermajority. While both of these are unlikely, how close we are to one or the other will make a big difference in how effective the fascist takeover will be.

I personally think Trump is likely to win no matter who the candidate but having a stronger candidate will have a meaningful effect on other races that matter greatly.

Humphrey is only a single data point. We can’t draw much of a conclusion from a single event. Maybe Humphrey lost due to the nomination process but I think it’s more likely he was just a weaker candidate. Particularly regarding his pro-Vietnam war stance which was very controversial at the time.