What Is a Circuit Split?

A circuit split happens when two or more of the United States courts of appeals decide the same federal legal question differently. One circuit reads a statute or a constitutional provision one way; another circuit, facing a similar case, reads it the opposite way. Until something resolves the disagreement, the same conduct can be lawful in one part of the country and unlawful in another, simply because of which appeals court has jurisdiction there.

The thirteen circuits

The federal appellate system is divided into thirteen circuits. Eleven are numbered regional circuits, each covering a group of states or territories. The D.C. Circuit covers only Washington, D.C., and handles a disproportionate share of administrative and regulatory appeals because so many federal agencies are headquartered there. The Federal Circuit is different again: instead of a geographic territory, it has nationwide subject-matter jurisdiction over specialized areas of law, including patents and certain claims against the federal government. Every one of these courts can, and sometimes does, read the same federal statute or constitutional question differently from its sister circuits.

A split can form for ordinary reasons. Judges are interpreting language that Congress or the Constitution left ambiguous, they are working from different precedents within their own circuit, and they are not bound by another circuit's reasoning. Nothing requires the Fifth Circuit to follow the Ninth Circuit's answer to a question neither the Supreme Court nor Congress has settled. A split can persist for years before anyone with the right case asks the Supreme Court to resolve it.

Why splits lead to certiorari

Supreme Court Rule 10 opens by making clear that review on certiorari "is not a matter of right, but of judicial discretion," and that a petition "will be granted only for compelling reasons." Rule 10 then spells out what counts. Under Rule 10(a), a U.S. court of appeals has decided a federal question in a way that conflicts with another U.S. court of appeals on the same matter. Under Rule 10(b), a state court of last resort has decided a federal question in a way that conflicts with another state's highest court or with a federal court of appeals. Under Rule 10(c), a court has decided an important federal question the Supreme Court has not settled, or has settled it in a way that conflicts with the Supreme Court's own precedent.

That first category, the plain circuit split, is one of only a handful of reasons Rule 10 spells out by name, and practitioners and the Court's own framing treat it as a leading reason cert gets granted. It is not the only reason, and it is not a numerically quantified share of the docket. Rule 10 lists it alongside conflicts involving state courts of last resort and unsettled important federal questions as independent, freestanding grounds, so a circuit split is best understood as a strong signal, not a guarantee, that the Court will take a case.

The argument for waiting, and the argument for stepping in

Whether the Court should jump on every circuit split, or let a split "percolate" across circuits for a few years first, is a genuine and long-running disagreement among judges and scholars, and Rule 10's discretionary language leaves room for the Court to do either.

The case for resolving a split quickly is uniformity: federal law is supposed to apply the same way regardless of which state or region a person is in, and a live split means identical conduct can be treated as legal in one circuit and illegal in another for as long as the disagreement lasts. The case for letting a split percolate is that more circuits weighing in, over more sets of facts, can sharpen the question and expose arguments that a single early case might have missed, so that by the time the Supreme Court does step in, it has the benefit of several courts' worth of reasoning to draw on. Both views accept Rule 10's underlying premise, that a circuit split is a compelling reason to grant cert; they differ on how quickly "compelling" should translate into "granted."

Either way, a circuit split does not resolve itself. Until the Supreme Court grants cert and rules, or Congress amends the statute at issue, the conflicting circuit precedents each remain binding within their own circuits, and litigants on the wrong side of a favorable circuit's rule are often the ones with the strongest incentive to ask the Supreme Court to finally settle the question nationwide.