Democrats and Republicans disagree about Covid-19 facts, in a divide that goes beyond usual political partisanship

Politics can divide even friends and families. When this happens, we like to tell ourselves that the explanation lies in honest differences in values and preferences. From this standpoint, friends from different political parties won’t really disagree, for example, about the number of workers displaced in the pandemic, but they might differ on who should bear the costs. It’s another matter, however, if political conflict results from differences in information or attachments to alternative realities.

It’s possible to disagree — but still engage — with friends or fellow citizens who...