If a state court rules, for example, that a particular state law is unconstitutional under the state constitution, can this decision be overturned by a federal court?

2 Answers 2



Federal courts, when sitting in diversity jurisdiction,* are obligated to follow state law as articulated by state courts, as the Supreme Court ruled in Erie Railroad Company v. Tompkins. If there is no controlling state court precedent, the federal court may "guess" how the state supreme court would have ruled, but for particularly important issues of law, it is preferable for the federal court to certify the question to the state supreme court instead.

Under no circumstances may a federal court second-guess a state supreme court's determinations of state law. A federal court may find that a state law conflicts with a federal statute or with the (federal) Constitution, but it may not say, for example, "the state supreme court got the (state) law wrong."

* It is unlikely that a state law would be relevant under any other theory of federal jurisdiction, but 28 USC 1652 does not explicitly limit the doctrine to diversity jurisdiction, so in the implausible scenario where a court not sitting in diversity jurisdiction nevertheless has to apply state law, it must still follow the state law.

  • There are a few major areas outside of diversity cases where the federal judiciary must use state law. Copyright cases in particular are exclusively federal, but many such cases involve a licenses that are tied into contracts, and contracts are governed by state law. Side claims in in a controvery with specifically federal character can also pull in state law (although many such cases will also be diversity cases). Diversity cases probably are the most common reason though. Commented Dec 4, 2023 at 15:51
  • Would it be possible for someone to argue in federal court that a state court's judicial conduct in a case violated e.g. 14th Amendment protections--that the law as written by the legislature was compatible with the Fourteenth Amendment, but that judges were e.g. capriciously ignoring the statute to the detriment of one of the parties on account of race?
    – supercat
    Commented Dec 4, 2023 at 18:08
  • Doesn't this assume supreme court precedents cannot be thrown out? The US court system is currently "whatever SCOTUS decides" (Dobbs v. Jackson Women's Health Organization) (Citizens United) (Janus v. Council Number 31), (Ramos v. Louisiana), how it ruled in previous cases is no longer binding in practice. To determine what SCOTUS will decide, we need to look at what the federalist society wants, not previous court case decisions, which will in turn depend on who benefits from the ruling.
    – Yakk
    Commented Dec 4, 2023 at 20:33
  • @Yakk: The Erie doctrine dates to the 1930s and is an extremely well-established principle of federalism. It is unlikely that the Federalist Society would want to overturn it, as doing so would infringe on state sovereignty.
    – Kevin
    Commented Dec 4, 2023 at 21:53
  • @supercat: Case law is considered a kind of law (under the American common law system). A state court decision that violates the (federal) Constitution is treated no differently to a state statute that violates the Constitution.
    – Kevin
    Commented Dec 4, 2023 at 22:02

Any cause of action advanced at the federal level must have a federal basis, such federal law, the federal constitution, or general legal principles accepted by the federal courts. Simply asserting that a lower court interpreted the state constitution incorrectly is not a federal cause of action. But a state court decision can be challenged in federal court if a federal basis for the challenge can be given. For instance, in Bush v. Gore, Bush argued that the Florida Supreme Court's order of a recount violated the Equal Protection clause of the federal constitution, and so stayed the order.

Also, you ask about a decision "that a particular state law is unconstitutional under the state constitution". This would be especially hard to argue in federal court, as it's likely that the only party with standing would be the state government, and it would rather weird for the state executive branch to ask the federal judicial branch to overrule the state judicial branch. Federal courts are for resolving disputes between individuals and the government, or between governments of different states, not disputes between different branches of the same state government.

A decision that a particular state law is constitutional is more likely to result in a federal basis for appeal, since anyone charged with a crime under the law would have standing. While they wouldn't be able to challenge the finding that the state constitution fails to bar the law in question, there are various other assertions that they would be able to assert. For instance, they could assert that the law violates the federal constitution. If they had originally argued that the state didn't have jurisdiction, and the state Supreme Court found that the state constitution does give jurisdiction, they could argue in federal court against the finding of jurisdiction. Etc.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .