Pollsters have long understood that the act of casting a ballot creates a bond. Once we have voted for a candidate, we feel invested in him. We don't want to admit to ourselves that we might have made a mistake.
Psychologists have lots of terms for the cognitive glitches that make us think this way: post-decision rationalization, dissonance reduction, commitment escalation, choice-supportive bias. But these phrases don't do justice to the sheer intensity of what happened in red states in November 2016. Voters who detested Hillary Clinton were emotionally fused to the man who defeated her. Something similar happened eight years later with Kamala Harris, soldering the attachment more firmly.
