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Key Facts
- Federal level: Procedural law supplies the rules a federal court uses to manage a case, while substantive law defines legal rights, duties, and remedies.
- Federal level: Federal civil procedure covers commencement, service, pleadings, motions, discovery, trial, judgment, and review.
- Federal level: The Rules Enabling Act authorizes federal procedural rules but provides that they may not abridge, enlarge, or modify substantive rights.
- Federal level: Constitutional due process places minimum limits on procedure, including legally adequate notice and an opportunity to be heard.
- Federal level: State procedure is not a single national system, and federal courts may apply state substantive law even while using valid federal procedural rules.
Procedural law is the body of rules that determines how a legal matter moves through a court or agency. It answers questions about starting a case, notifying parties, presenting claims and defenses, exchanging information, deciding motions, conducting a hearing or trial, entering judgment, and seeking review.
Substantive law answers a different question: what rights, duties, prohibitions, and remedies the law recognizes. The distinction is useful, but not always self-evident. A rule described as procedural can affect the practical ability to enforce a substantive right, so courts examine the governing authority and context rather than relying only on a label.
Federal civil procedure organizes the life of a case
The Federal Rules of Civil Procedure govern civil actions in United States district courts, subject to stated exceptions. They establish an interconnected process rather than a collection of isolated forms.
A civil action begins with a complaint. Service rules address formal notice. Pleadings identify claims and defenses. Motion rules permit courts to resolve legal issues, discovery rules govern information exchange, and trial and judgment rules govern final decision-making.
Procedure and substance come from different authorities
Congress authorized the Supreme Court to prescribe general federal rules of practice and procedure through 28 U.S.C. § 2072. The same statute says those rules may not abridge, enlarge, or modify a substantive right.
That boundary matters when federal and state law interact. Under 28 U.S.C. § 1652 and Erie Railroad Co. v. Tompkins, a federal court exercising diversity jurisdiction generally applies the substantive law of the relevant state. That does not mean the court automatically uses every state procedural rule.
In Hanna v. Plumer, the Supreme Court explained that a valid Federal Rule governs when it directly addresses the disputed procedural issue and stays within the Rules Enabling Act. When no Federal Rule directly controls, the Erie framework asks whether choosing a federal practice would improperly encourage forum shopping or unequal administration of law.
Procedural rules shape decisions without deciding every merit question
A motion can ask a court to decide an issue before trial. For example, summary judgment examines whether the record presents a genuine dispute of material fact and whether a party is entitled to judgment as a matter of law.
This illustrates how procedure can be outcome-determinative without itself defining the underlying right. The procedure sets the decision method and evidentiary threshold; the applicable substantive law identifies which facts are material and what legal consequence follows.
Due process creates a constitutional floor
Procedure is not merely administrative convenience. The Due Process Clauses constrain how government may deprive a person of life, liberty, or property.
In Mullane v. Central Hanover Bank & Trust Co., the Supreme Court held that notice must be reasonably calculated under the circumstances to inform interested parties and allow them to present objections. The precise procedure required varies with the setting, but an empty formality is not enough.
Federal procedure does not describe every court
Each state has its own constitutions, statutes, court rules, evidence rules, and local practices. Some state rules resemble the federal rules, while others use different deadlines, terminology, pleading standards, discovery limits, or appellate procedures.
This article explains the general concept through the federal civil system. It does not establish the procedure of any particular state court, criminal case, bankruptcy matter, administrative proceeding, or appellate court.
