The GOP is ideologically committed to policies designed to hurt the poor with no benefit to anyone else.
This brings in the votes of the rich, who see the poor as the people who steal their tax doors, and the racists, who see the poor as black people who might pass the racists on the economic ladder. Never mind that both groups are wrong.
Krugman sees this pattern extending into the future. But another answer to the rhetorical question at the end of today's column is: