Federalism, in which regional governments retain considerable power, has been invoked in the past to take away representational rights. But a local approach, properly applied, can also restore them. In a stinging dissent, Justice Elena Kagan pointed out that where the Supreme Court had failed to define and regulate partisan gerrymandering, four lower federal courts had succeeded.

State courts can do so, too — without federal approval. The elections clause of the Constitution gives states broad authority over redistricting as long as the actions do not run afoul of federal law. Chief Justice Roberts conceded that states can act on their own by “actively addressing the issue through state constitutional amendments and legislation.” Now that Republicans and their designates control the Supreme Court, the Senate and the presidency, reformers should embrace what Heather K. Gerken, the dean of Yale Law School, calls “progressive federalism.”

The Princeton Gerrymandering Project, which I founded, has investigated federalist approaches to redistricting reform. We found 27 instances in which a district map was overturned on the basis of state law. Recently, Pennsylvania’s Supreme Court overturned an unfair congressional map, citing the state Constitution’s free and equal elections clause, a phrase that is also found in 27 other state Constitutions.