For decades, the dominant assumption has been that people-of-color in the USAwould find their natural political home within the Democratic Party. The nation’s growing racial and ethnic diversity seemed to ensure the left’s electoral future. I have been studying the movement of nonwhite voters to the right for 15 years. When we began this work, people like Mr. Gibson were often disdained by liberals as dupes of the right voting against their own interests, votes they would regret once they saw their conservative beliefs in action. But seven years later, Mr. Gibson seems to be much less of an anomaly....