Don’t you think they KNOW they will lose? The trouble will start way ahead as the season heats up. Democrat Convention Milwaukee. Like 1988 Iran vs. Iraq.
The Dem Presidential nominee will be determined by Super delegates at the party convention. The group think that will be occurring will convince them and their followers that they can not loose. They will initiate a vote harvesting cheating scheme that will convince they must win.
When they don't the only explanation they will accept is that Trump cheated. Been there done that.