2.1 Sources of Law & Precedent

Every research assignment a paralegal touches — a memo on a slip-and-fall claim, a cite check for a brief, a regulation lookup for a compliance question — starts with the same foundational skill: knowing where law comes from and which source controls when two sources collide. The NALA Certified Paralegal (CP) Knowledge Exam tests this directly, so commit the hierarchy to memory.

The Five Primary Sources of Law

1. Constitutions

The United States Constitution is the supreme law of the land. Article VI — the Supremacy Clause — provides that the Constitution, federal laws made in pursuance of it, and treaties are supreme over conflicting state law. Every state also has its own constitution, which is the highest authority on questions of state law within that state. A state constitution may grant more rights than the federal Constitution but never fewer.

2. Statutes

Statutes are laws enacted by legislative bodies — Congress at the federal level, state legislatures at the state level. Federal statutes are codified in the United States Code (U.S.C.), organized into titles by subject (for example, Title 28 governs the judiciary and judicial procedure). Before a statute takes effect, it begins as a bill; at the federal level, a bill must pass both the House and the Senate in identical form and then be signed by the President (or survive a veto override by a two-thirds vote of each chamber). Statutes trump conflicting common law — when the legislature speaks, judge-made law on the same point yields.

3. Case Law (Common Law)

Common law is judge-made law, developed decision by decision and inherited from the English legal system. When no statute or constitutional provision controls an issue, courts resolve it by applying and extending prior decisions. Areas such as negligence, contract formation, and property doctrine remain heavily common-law driven. Appellate decisions — not trial-level rulings — create the precedent that other courts follow. Published opinions are collected in reporters (e.g., the Federal Reporter for the federal courts of appeals).

4. Administrative Regulations

Administrative regulations are rules promulgated by agencies (the Environmental Protection Agency, the Internal Revenue Service, the Occupational Safety and Health Administration) under authority delegated by statute. A properly adopted regulation has the force of law — it is not merely advisory. Federal regulations are published first in the Federal Register and then codified in the Code of Federal Regulations (C.F.R.).

5. Ordinances

Ordinances are enactments of local governments — city councils, county boards. Zoning rules, noise limits, and local licensing requirements are typical ordinances. They sit at the bottom of the hierarchy and are valid only so far as they do not conflict with state or federal law.

Binding vs. Persuasive Authority

Primary authority is the law itself — constitutions, statutes, regulations, and cases. Secondary authority (treatises, law review articles, legal encyclopedias such as American Jurisprudence, restatements) explains the law but is never binding.

Within primary authority, the exam's favorite distinction:

• Binding (mandatory) authority — a source the court must follow: the Constitution, applicable statutes, and decisions of higher courts in the same jurisdiction. For a federal district court in Texas, Fifth Circuit precedent is binding.
• Persuasive authority — a source the court may consult but need not follow: decisions from other circuits, other states, trial-level courts, and well-regarded secondary sources. A Ninth Circuit ruling may be cited to a Fifth Circuit judge, but it cannot control the result.

Stare Decisis

Stare decisis — Latin for "let the decision stand" — is the doctrine that courts adhere to precedent. It operates in two dimensions:

1. Vertical stare decisis: lower courts must follow the decisions of higher courts within the same judicial system. This dimension is essentially absolute.
2. Horizontal stare decisis: a court generally follows its own prior decisions, though appellate courts — and especially the U.S. Supreme Court — may overrule their own precedent when it proves unworkable or wrongly decided.

A party avoids an unfavorable precedent primarily by distinguishing it — showing that the facts or legal issue differ materially — rather than by asking the court to overrule it. When no prior case exists in the jurisdiction, the matter is a case of first impression, and the court looks to persuasive authority for guidance.

Paralegal Scenario

Your supervising attorney asks you to research whether a client's arbitration clause is enforceable in federal court in Louisiana. You find a directly on-point Fifth Circuit case upholding such clauses and a California state case striking a similar clause down. Your memo should lead with the Fifth Circuit decision: it is binding authority on federal courts in Louisiana. The California case is, at most, persuasive — flag it only if the facts are unusually close.

Common Exam Traps

• Reversing the hierarchy: an administrative regulation never overrides the statute that authorized it, and no statute overrides the Constitution.
• Treating out-of-state or out-of-circuit case law as binding. It is persuasive only.
• Confusing the Federal Register (daily publication of proposed and final rules) with the Code of Federal Regulations (the codified, organized compilation).
• Assuming trial court opinions create binding precedent — they generally do not bind even the same court in a later case.