For years, the right has been frustrated by the left’s ability to unite various interest groups successfully as a force. The right hasn’t had as much success, with factions calling each other RINOs and lecturing about Reagan’s 11th Commandment. Now, it looks like the left’s ability to work together is finally unraveling. It is happening because the left has become increasingly obsessed with identity politics, labeling everyone in groups and stereotypes instead of as individuals. As we all learned from history, grouping people by race resulted in terrible things like slavery. It is unsustainable, as it breeds resentment toward other...