This is part of Opinionpalooza, Slate’s coverage of the major decisions from the Supreme Court. The best way to support our work—and unlock exclusive legal analysis—is by joining Slate Plus. (If you are already a member, consider a donation or merch!)

In the month since the Supreme Court gutted what was left of the Voting Rights Act in Louisiana v. Callais, our Constitution’s promise of multiracial democracy has come under concerted attack. Across much of the South, state legislatures have acted with lightning speed to enact new maps designed to strip communities of color of the ability to elect representatives of their choice, going to the extreme of rescheduling primary elections already in progress to wipe out Black representation. Callais not only permitted states to draw maps that entrench white control; it made up the rule that Congress has only limited power under the 15th Amendment to enforce the promise of racial equality at the polls. While scrapping the crown jewel of the Civil Rights Movement, Callais made it much harder to pass new federal voting-rights legislation to enforce the 15th Amendment’s ban on racial discrimination in voting.

With Congress’ weakened ability to enforce the 15th Amendment, post-Callais fights over voting rights may depend on additional sources of federal voting-rights authority. Perhaps the most important of these is the Constitution’s guarantee clause, which provides that “the United States shall guarantee to every state in this Union a Republican Form of Government.” Though not well known and perennially underenforced, this clause provides an important hook for congressional action to safeguard an inclusive, multiracial democracy. It imposes a duty on the federal government to prevent states from sliding into oligarchy or other antidemocratic forms of government. In this way, it helps ensure what President Abraham Lincoln........

© Slate