By your logic psychologists cannot comment on political matters. Why not? Trump was even in the title. If you do not want to read it, it would be easy to avoid. Political behavior is behavior and I walked out why there are underlying psychological processes involved for these political decisions that go beyond simple categories that I reject here as adequate (e.g., "Trump supporters are racists".) I think you would agree that our internal world is part of our political choices. That is obvious, no? This blog was written 4 years ago and the data on those processes and their impact -- I described only one study here -- is now even clearer. We as a human community are going through challenging times and our psychological flexibility is being tested. We see it all across the globe, in mental health, suicide rates, loneliness, political polarization, and the emergence of more authoritarian regimes of the left and the right (my wife is Brazilian -- Brazil is an example; Putin is an example; etc). As for prejudice being useful in some ways -- sure. We've studied that too. It makes cognitive judgments faster for example. But in a world in which "us" and "them" is reorganizing at light speed, we have to change what we mean by "us." The coronavirus is a clear example of why. We are not isolated tribes anymore, and we need modern minds for this modern world. I walk through all if this in the book "A Liberated Mind" if you want to know the science behind it. - S