Sen. Lindsey Graham has been one of the most prominent. At the start of this week, Sen. Lindsey Graham said that if mail-in votes are counted the Republican Party will never win an election again.
This could be the end of the Southern states suppressing voters. More voters mean more Democratic voters. Throw in the under 30's who are overwhelmingly Democratic anyway, and the Republicans are toast.
This is why they are supporting Trump. He is their last throw of the dice. A dying ideology.
The Republicans will need to reinvent themselves, or the Democrats will split into 2 parties with the new left and new right.