Mark Lilla writes a great analysis of the rise of identity politics in the Wall Street Journal, The Liberal Crackup
All that began to change when the New Left shattered in the 1970s, in no small part due to identity issues. Blacks complained that white movement leaders were racist, feminists complained that they were sexist, and lesbians complained that straight feminists were homophobic. The main enemies were no longer capitalism and the military-industrial complex; they were fellow movement members who were not, as we would say today, sufficiently “woke.”
It was then that less radical liberal and progressive activists also began redirecting their energies away from party politics and toward a wide range of single-issue social movements. The forces at work in healthy party politics are centripetal; they encourage factions and interests to come together to work out common goals and strategies. They oblige everyone to think, or at least to speak, about the common good.
In movement politics, the forces are all centrifugal, encouraging splits into smaller and smaller factions obsessed with single issues and practicing rituals of ideological one-upmanship. Symbols take on outsize significance, especially in identity-based movements.
The results of this shift are now plain to see. The classic Democratic goal of bringing people from different backgrounds together for a single common project has given way to a pseudo-politics of self-regard and increasingly narrow and exclusionary self-definition. And what keeps this approach to politics alive is that it is cultivated in the colleges and universities where liberal elites are formed. Here again, we must look to the history of the New Left to understand how this happened.
The Republicans were weakened by their litany of litmus tests. The pro life crowd, the school prayer crowd, or the gun rights advocates would be intolerant of any variation from the orthodox position on THEIR issue. The Democrats were unified and won elections even with less than 50% of the vote.
Now the Democrats have fractured themselves and lost what was a critical advantage.