Everyone is entitled to his own opinion, but not his own facts, as United States Senator Daniel Patrick Moynihan was fond of saying. But it is not merely facts that are under assault in the polarized politics of the US, the UK, and other nations twisting in the winds of populism. There is also a troubling assault on reason. Authoritarian tendencies know that warping the facts is only a start. Warping reason and logic and clarity of thought is the holy grail.