The Supreme Court will hear one of the most significant election law cases . . . well, ever . . . on December 7. (Yes, infamy.) In Moore v. Harper, two North Carolina legislators seek to upend the system of checks and balances that has governed federal election administration since the founding. They’ve asked the Supreme Court to endorse the “independent state legislature theory,” a dubious reading of the Constitution that holds that the only entity in a state that can make rules for federal elections is the legislature. The theory could render governors, state courts, and even state constitutions powerless to prevent abuses when it comes to federal elections.

As the Brennan Center has warned, the independent state legislature theory would give lawmakers a free hand to adopt partisan gerrymanders, and it would remove checks on vote suppression.

In big Supreme Court cases, the amicus ("friend of the court") briefs matter greatly. They can bring before the justices facts and perspectives well beyond the immediate litigation — a Greek chorus that reminds us of the vast potential impact of a democracy ruling. Last week, the amicus briefs on the pro–voting rights side poured into the Supreme Court. It was a rather breathtaking lineup.

It included the cofounder of the Federalist Society. The top early American historians. The dean of Georgetown Law School, who is the country’s leading expert on what judicial review meant in the framing era. Former California Gov. Arnold Schwarzenegger. Civil rights and voting rights groups. Forty-eight briefs in all, on top of the devastating submission filed earlier by the conference of the chief justices of all 50 states, who pointed out their own vital role in upholding the constitutional order.

The Brennan Center filed a brief as well. Our focus: the impact that an unwise ruling could have on hundreds of constitutional provisions, hundreds of state court decisions, and more than 650 delegations of authority by state legislatures to other state officials to administer federal elections — the basis for thousands of policies. Lawyers know this kind of brief as a “Brandeis brief,” named after a famous filing by the great public interest lawyer Louis Brandeis before he was on the Supreme Court himself. Our brief did not focus on doctrine but on facts: the tangible, real-world consequences of a bad ruling.

Here are some examples of the chaos that would ensue.

State constitutional guarantees could disappear. All state constitutions but one guarantee the right to vote, and 27 guarantee free, fair, equal, or open elections. Sixteen state constitutions guarantee access to absentee or mail voting, while fourteen establish standards or processes for drawing congressional districts. The independent state legislature theory could nullify these state constitutional commitments.

Voting reforms could be abandoned. At least eight states have used direct democracy, such as voter referendums, to modify their voting methods. The citizens of Michigan, for example, adopted no-excuse absentee voting in 2018. In other states, voters have changed the way that winners are selected. Alaska, for example, adopted ranked-choice voting by referendum in 2020. Those provisions might no longer have the force of law for federal elections if the Supreme Court adopts the independent state legislature theory, and the legislatures would be free to ignore the voters’ demands.

The authority of countless election officials would be questioned. Every state legislature in the country has delegated some portion of its election administration authorities to other state and local officials. In some states, such as Tennessee and Vermont, local officials have discretion over what time polls should open and close in their communities. Nearly every state legislature has empowered local officials to determine where polling places should be located. In most states, state and local officials have broad powers to adopt regulations over elections. These delegations are essential because legislatures are ill-suited to make quick decisions in response to the rapidly changing realities of running an election. A Georgia statute, for example, allows individuals to challenge the registration of a voter and requires county officials to immediately decide whether there is probable cause to sustain the challenge. The law, however, offers no standard or process for making such a determination. The secretary of state issued guidance to provide some statewide rules for how challenges may be resolved, while leaving discretion to county officials to determine the process for resolving challenges. The independent state legislature theory would open all of these delegations, and the thousands of resultant policies, to legal challenge.

This is just a taste of the disorder that would follow the adoption of the independent state legislature theory. Maintenance of voter lists, security of registration records, mail voting processes, drop boxes, emergency powers, voter identification requirements . . . the list goes on. Our entire system of election law requires a sharing of power and responsibility across branches of state government. The Supreme Court is being asked not just to rule in one ill-considered case — it’s being asked to upend the entire system of elections in the United States. One more reason it should, and I hope and expect will, rule against the power grab.