"They can listen to the base, or they can stiff it and get smashed themselves."
So if they retain control of Congress, or even gain seats, will we have a better idea of who the "base" actually is?
No. It isn't a mystery. The issues on which they are out of step with the party are known to everyone. They consist of places where 80% of the population - let alone of the party - want one thing, and they do the opposite. Presumably because lobbyists or cocktail party hostesses want them to, or maybe just because they are so insulated from reality they don't get it.