In praise of polarization

How identity politics changed the Democratic Party — for the better.

Polarization, party sorting, and identity politics are central villains of our time. Politicians lament them. Pundits loathe them. Book after book has been written blaming them for society’s ills, from the decline of reason to the electoral travails of the Democratic Party to the death of American democracy.

But the past month of sustained, mass activism against police brutality offers evidence for the defense — that sorting around identity can be inclusive, that polarization can be productive.

The historically...