All of this is tied to the psychology of accommodation. As a conservative-leaning clinical psychologist I know explained to me, when new experiences don’t fit into an existing schema — Mr. Trump becoming the leader of the party that insisted on the necessity of good character in the Oval Office when Bill Clinton was president, for example — cognitive accommodation occurs.

When the accommodation involves compromising one’s sense of integrity, the tensions are reduced when others join in the effort. This creates a powerful sense of cohesion, harmony and group think. The greater the compromise, the more fierce the justification for it — and the greater the need to denounce those who call them out for their compromise. “In response,” this person said to me, “an ‘us versus them’ mentality emerges, sometimes quite viciously.”

“What used to be a sense of belonging,” I was told, “devolves into primitive tribalism, absolute adherence to the leader over adherence to a code of ethics.”