I would say that the racist vote is a fair percentage of the GOP vote every Presidential election. The problem is, every four years there are fewer racists and more minorities.
The only reason the GOP is holding the fort in the statehouses and Congress is that the Democratic voters, who proportionately are younger and more nonwhite, are not used to voting and so can only be motivated every four years. However, once a person has voted several times, they tend to make it a regular thing and those once-every-four-years Democratic voters will inevitably become once-a-year voters. When that happens, the GOP's goose is cooked. At full strength, there are more Democrats than Republicans.