What actually makes authority mandatory?
Authority is mandatory only when both conditions are met. First, it must be primary law — enacted law or a judicial decision, not commentary about law. A Restatement section, a treatise, a law review article, and an ALR annotation are secondary authority and can never be binding, no matter how respected. Second, it must come from a body with power over the deciding court: the legislature whose statutes govern the dispute, or a court that sits above the deciding court in the same appellate line.
Do not collapse the primary/secondary distinction with the mandatory/persuasive distinction. They are independent axes. A California Supreme Court opinion is primary and mandatory in a California trial court, primary and merely persuasive in an Oregon trial court. The Restatement (Second) of Contracts is secondary and persuasive everywhere — until a state's highest court adopts a section, at which point the adopting opinion (not the Restatement text) becomes the binding authority.
Within a binding opinion, only the holding binds. Dicta — reasoning not necessary to the result — is persuasive even when it comes from the court directly above you. This is where most arguments about "controlling precedent" are actually fought: the parties agree the case is binding and disagree about how much of it was holding.
Which courts bind which?
Vertical stare decisis runs down a single appellate chain. Horizontal stare decisis — a court following its own prior decisions — is a strong practice but not the same obligation; the U.S. Supreme Court can overrule itself, and state high courts can overrule themselves. Federal circuit panels are a special case: under each circuit's law-of-the-circuit or prior-panel rule, one panel cannot overrule another; only the en banc court or an intervening Supreme Court decision can.
The single most-missed rule: a state court deciding a federal question is bound only by the U.S. Supreme Court, not by the federal court of appeals for the circuit in which the state sits. A Texas appellate court may find Fifth Circuit precedent on a federal statute highly persuasive and still reject it. See Lockhart v. Fretwell, 506 U.S. 364 (1993) (Thomas, J., concurring).
- U.S. Supreme Court: binds every court in the country on federal law and the federal Constitution.
- Federal court of appeals: binds the district courts within its own circuit; persuasive only to district courts and sister panels elsewhere.
- Federal district court: binds no one, not even the same judge in the next case; district opinions are always persuasive.
- State high court: binds every court in that state on state law, and binds federal courts applying that state's law.
- State intermediate appellate court: binds trial courts in its state (in most states, and in some states only within its own district or department — check).
- Sister-state decisions, sister-circuit decisions, and every foreign court: persuasive only.
What happens when a court applies another sovereign's law?
Under Erie Railroad Co. v. Tompkins, 304 U.S. 64 (1938), a federal court sitting in diversity applies state substantive law, and the state's highest court is the authoritative source. If that court has not decided the question, the federal court makes an Erie guess about how it would rule. Decisions of intermediate state appellate courts are treated as strong evidence of state law but are not controlling if the federal court is convinced the state high court would decide otherwise. Compare Commissioner v. Estate of Bosch, 387 U.S. 456 (1967) (federal court owes lower state court rulings "proper regard," not automatic deference).
The mirror problem: when a state court applies federal law, the Supremacy Clause makes U.S. Supreme Court holdings binding, and nothing else in the federal system is. When a federal court applies federal law, a prior circuit decision that appears inconsistent with later Supreme Court reasoning still controls until it is overruled — lower courts must follow directly controlling precedent and leave overruling to the Supreme Court. Rodriguez de Quijas v. Shearson/American Express, Inc., 490 U.S. 477 (1989); Agostini v. Felton, 521 U.S. 203 (1997).
How much weight does persuasive authority actually carry?
Persuasive authority is not a single category with a single weight. Rank it, and tell the reader why the source deserves attention. The factors judges actually respond to are the identity of the court, the quality of the reasoning, factual similarity, recency, and whether the source represents a trend or an outlier.
Practical hierarchy, from strongest down: a decision of your own jurisdiction's high court that is close but not squarely on point; decisions from sister circuits or sister states, especially where courts have historically borrowed from each other or where the statutes are identical uniform acts; well-reasoned federal district or state trial decisions; Restatements and uniform act comments; leading treatises (Wright & Miller, Corbin, Williston, Moore's); law review articles; dissents and concurrences from binding courts.
Two specialized persuasive sources are worth knowing. Uniform and model laws — the UCC, the Model Penal Code, the Uniform Commercial Code comments — carry unusual weight because other states' interpretations of identical text are treated as interpretive aids. And legislative history, in jurisdictions that use it, is persuasive material about the meaning of mandatory text, not authority in its own right.
Where do unpublished and non-precedential opinions fit?
Federal Rule of Appellate Procedure 32.1 bars courts from prohibiting citation to federal judicial opinions designated "unpublished," "not precedential," or the like, if issued on or after January 1, 2007. But permission to cite is not precedential force. Circuits routinely provide by local rule that their unpublished dispositions do not bind future panels; they are persuasive only, and some circuits discourage citing them when published authority exists.
State practice varies sharply. Some states permit free citation of unpublished decisions; others forbid citing them for any purpose. California Rule of Court 8.1115 is the strictest well-known example, generally barring citation of unpublished California appellate opinions. Before you cite anything marked unpublished, read the local rule of the specific court you are filing in.
How do you show the difference in a memo or brief?
Structure signals authority. Lead the rule section with the binding source and state its provenance in the text: "Under section 4 of the Act, as construed by the Supreme Court of Ohio in X, ..." Then introduce persuasive material with an explicit label — "Although no Ohio court has addressed this, the Sixth Circuit and three sister states have held ..." Never let a reader discover from the citation that your key case is from Nevada.
In citation form: Bluebook Rule 1.4 orders string cites by authority — constitutions, then statutes, then cases, with federal before state and higher courts before lower. Rule 10.4 requires the court and jurisdiction in the parenthetical, which is precisely how a reader checks bindingness, so never omit it. Use Rule 10.6.1 parentheticals to flag weaker sources: (Thomas, J., concurring), (per curiam), (unpublished table decision). Use "see" or "cf." under Rule 1.2 when the persuasive case supports by analogy rather than directly.
One drafting habit will save you: after you write the rule statement, ask of every cited source, "Is this court above the court I am writing to, in the jurisdiction whose law governs?" If yes, it is mandatory and you should argue it. If no, it is persuasive and you owe the reader a reason to care.