How to Find Binding Authority

Two conditions must both be met. First, jurisdiction: the authority must come from the sovereign whose law governs the issue. Second, hierarchy: if it is case law, it must come from a court whose decisions your court is obligated to follow — usually a court directly above it in the same appellate chain, or a prior panel of the same appellate court.

Enacted law comes first and outranks case law. Within a jurisdiction the order is constitution, then statute, then validly promulgated regulation, then judicial decisions construing those texts. A case interpreting a statute that the legislature has since amended is not binding on the amended text. Students lose points constantly by leading with a case when a controlling statute or procedural rule answers the question.

Vertical stare decisis binds lower courts to higher courts in the same system. Horizontal stare decisis binds a court to its own prior decisions — strongly in the federal courts of appeals under the 'law of the circuit' rule, where one panel cannot overrule another absent en banc rehearing or intervening Supreme Court authority.

Ask three questions in order: Which sovereign's substantive law applies? Which court will decide the case? What kind of issue is it — substantive or procedural?

A federal court sitting in diversity applies state substantive law under Erie Railroad Co. v. Tompkins, 304 U.S. 64 (1938), and is bound by the decisions of that state's highest court. It is not bound by the state's intermediate appellate courts, though it treats them as strong evidence of state law and follows them absent persuasive indication the high court would rule otherwise. On federal procedure it applies the Federal Rules and binding circuit precedent.

State courts are bound by the U.S. Supreme Court on questions of federal law, but they are not bound by the federal court of appeals covering their geographic area, and they are not bound by federal district courts. A California trial court is free to disagree with the Ninth Circuit on the meaning of a federal statute, though it will usually say why.

If a contract has a choice-of-law clause, or the facts implicate more than one state, run the forum's choice-of-law rules first. The binding authority you need may be from a state you never expected.

Federal side: the U.S. Supreme Court binds every court in the country on federal law. A court of appeals binds the district courts within its circuit and later panels of itself. Circuits do not bind each other; a Second Circuit case is persuasive only in the Ninth. District court decisions bind no one — the Supreme Court noted in Camreta v. Greene, 563 U.S. 692 (2011), that a district judge's ruling is not binding precedent in another district, the same district, or even on the same judge in a later case.

State side: the structure varies by state, and this is the variation that matters most. In most states, the highest court binds all lower courts, and an intermediate appellate district binds only the trial courts within its own territory. California is different: under Auto Equity Sales, Inc. v. Superior Court, 57 Cal. 2d 450 (1962), any published Court of Appeal decision binds every superior court in the state, and where districts conflict, the trial court may choose between them. New York follows a similar statewide rule under Mountain View Coach Lines, Inc. v. Storms — an Appellate Division decision binds all trial courts in the state unless the trial court's own Department has held otherwise. Texas, Florida, and others use the narrower district-only model. Check your state's rule before assuming.

Also watch for two case-specific binding doctrines that are not stare decisis: law of the case, which locks in a court's own earlier rulings in the same litigation, and the mandate rule, which requires a lower court on remand to follow the appellate court's specific instructions.

Set the jurisdiction filter before you run a single search. On Westlaw and Lexis, restricting to your jurisdiction plus the courts above it eliminates the most common student error — building an argument on an out-of-circuit case that reads beautifully and binds nothing.

Then move from enacted law outward. Start in the annotated code (U.S.C.A./U.S.C.S. or the state annotated code) for the governing statute; the Notes of Decisions under each subsection are curated lists of cases construing that exact language, sorted by court. From one good case, use headnotes and the West Key Number System to pull other cases on the same point within your jurisdiction. A treatise or state practice guide will name the leading controlling case faster than any search string.

Read the court parenthetical in every citation you collect. Under Bluebook Rule 10.4, the parenthetical identifies the deciding court — '(9th Cir. 2001)', '(N.D. Cal. 2019)', '(Cal. Ct. App. 2015)'. That parenthetical is the binding-authority test in miniature, both for you and for the judge reading your brief.

Dicta does not bind. Only the holding — the resolution of an issue necessary to the judgment — carries stare decisis weight. Language about hypotheticals, alternative rationales the court expressly declined to reach, and sweeping statements untethered to the facts are persuasive at best, and opposing counsel will say so.

Fractured opinions bind only narrowly. Under Marks v. United States, 430 U.S. 188 (1977), when no rationale commands a majority, the holding is the position taken by the Justices who concurred on the narrowest grounds. Identify that opinion before you quote the plurality.

Unpublished and nonprecedential decisions vary. Federal Rule of Appellate Procedure 32.1 permits citing federal unpublished dispositions issued on or after January 1, 2007, but permission to cite is not precedential force — most circuits still treat them as nonbinding, a rationale explained in Hart v. Massanari, 266 F.3d 1155 (9th Cir. 2001). State rules differ sharply; California generally forbids citing unpublished opinions at all. Check the local rule.

Finally, a case that has been vacated, reversed, or depublished is not authority, and a case whose facts are materially different may be binding in the abstract but useless to you. Being bound to follow a rule and being helped by it are different things.

Run every case through KeyCite (Westlaw) or Shepard's (Lexis) before you cite it, and read the negative treatment rather than trusting the flag color. A red flag may reflect reversal on an unrelated issue; a yellow flag may reflect a single out-of-state disagreement that does not touch your point.

For statutes, verify the currency date on the code version and check for pending or recent amendments, plus any legislative override of the case you found. For regulations, check the current C.F.R. and then the Federal Register for later action.

Note the counterintuitive rule about erosion: even when later Supreme Court decisions have undermined a precedent's reasoning, lower courts must keep following the directly controlling case until the Court itself overrules it. See Rodriguez de Quijas v. Shearson/American Express, Inc., 490 U.S. 477 (1989), and Agostini v. Felton, 521 U.S. 203 (1997). 'It's been discredited' is not a basis for a district court to ignore binding precedent — though it is a fine argument for cert.

Say so, plainly, and then argue by analogy. Judges respect a memo that states 'no [jurisdiction] court has addressed this question' far more than one that disguises persuasive authority as controlling.

Build the persuasive hierarchy deliberately: binding authority on an analogous issue in your jurisdiction, then decisions of other courts in your jurisdiction, then other jurisdictions construing identical statutory language, then Restatements, model codes, and treatises, then law review commentary. Sister-state decisions interpreting a uniform act adopted in your state are unusually persuasive because uniformity is the point of the act.

In federal court facing an unsettled question of state law, remember certification: most states let a federal court certify a controlling question to the state's highest court. That converts a guess into binding authority, and it is worth flagging in a memo.