Common Law Systems

Every legal system answers a basic question: where does the law come from? Common law systems answer with layers rather than a single code. The first layer is the common law itself — the accumulated decisions of courts resolving real disputes over centuries. Judges did not simply apply existing rules; in deciding cases they articulated principles that later courts adopted, refined, or distinguished. The second layer is legislation. In England and Wales, Parliament enacts statutes that apply across the jurisdiction; in the United States, Congress legislates federally while state legislatures legislate for each state, and a written constitution governs the relationship between those levels. The third layer is equity, which began as a corrective jurisdiction and remains a distinct source of doctrines and remedies, as later chapters explain. The hierarchy of these sources differs between the two jurisdictions. In the United States, the federal constitution is supreme law, and statutes inconsistent with it can be invalidated. In England and Wales, the absence of a codified constitutional text means the relationship between statute and the common law is governed by different principles, including the doctrine of parliamentary sovereignty as conventionally understood. The Interpretation Act 1978, published by The National Archives, illustrates how even the reading of statutes is itself governed by legislation, supplying default interpretive rules that apply unless a statute provides otherwise. For a learner, the practical habit is to ask three questions of any legal problem: which jurisdiction applies, which source of law governs, and how the sources rank. Those questions frame everything that follows, beginning with the doctrine that gives common law its name.

Precedent is the doctrine that gives common law systems their characteristic texture. Its core commitment is consistency: courts decide like cases alike, and earlier decisions guide later ones. The mechanics rest on two distinctions. First, within a judgment, the ratio decidendi — the legal reasoning essential to the outcome — is what binds; statements made in passing, the obiter dicta, may persuade but do not bind. Second, binding force is vertical: a decision binds courts below it in the same hierarchy, not courts above or beside it. In England and Wales, the hierarchy described by the Courts and Tribunals Judiciary places the UK Supreme Court at the summit, with the Court of Appeal and the High Court beneath it; the Supreme Court's own materials describe its role as the final court of appeal for the United Kingdom, hearing points of the greatest public importance. The United States adds a horizontal dimension: because federal and state systems run in parallel, federal courts follow federal precedent, state courts follow state precedent, and the US Supreme Court's rulings on federal law bind courts in both systems. Whether a court may depart from its own prior decisions is a separate question, and the answer differs by jurisdiction and by court. Precedent also depends on infrastructure: without accurate law reporting, later courts cannot know what was actually decided, which is why the history of law reporting is inseparable from the history of the common law. When evaluating any authority, the disciplined approach is always the same: identify the court, place it in the hierarchy, isolate the ratio, and only then assess its weight.

Legislation now supplies most of the operative rules in both jurisdictions, which makes interpretation a central judicial task. English courts historically articulated three classic approaches. The literal approach reads the words in their ordinary sense; the golden approach modifies that reading to avoid an absurd or repugnant result; and the mischief approach examines the defect the statute was enacted to cure. Modern English practice also directs courts to particular interpretive materials, and the Interpretation Act 1978 supplies default rules of construction — how defined terms operate, how certain common expressions are read — that apply across legislation unless displaced. American courts approach the same task with a different vocabulary. Textualism concentrates interpretive attention on the enacted words themselves; purposivism gives weight to the statute's broader objective. Some American judges consult legislative history — committee reports, floor statements, and similar materials — while others are skeptical of that practice, and the debate remains live across jurisdictions. Two structural differences deserve emphasis. First, the United States has a written constitution, so interpretation operates in the shadow of judicial review: a statute construed one way may survive, and construed another way may fall. Second, in both jurisdictions, interpretation feeds precedent. Once a court settles the meaning of a statutory phrase, that holding binds later courts, so the body of case law about a statute grows alongside the text itself. For learners, the takeaway is that interpretation is not a footnote to legislation; it is the point where the two great sources of common law authority — statute and case law — actively meet and shape each other.

Precedent only works if everyone knows which court outranks which, so court structure deserves careful attention. In England and Wales, the structure published by the Courts and Tribunals Judiciary distinguishes criminal and civil streams. Much criminal work begins in magistrates' courts, and much civil work begins in the County Court. The High Court handles more significant first-instance matters and certain appeals, the Court of Appeal hears appeals from the courts below, and the UK Supreme Court — described on its own website as the final court of appeal for the United Kingdom — sits at the top. The United States presents a dual picture. The federal system described by the Administrative Office of the US Courts runs from district courts through circuit courts of appeals to the US Supreme Court, while each state maintains its own complete hierarchy, and most cases are filed in state courts. Judicial review also takes different forms. In England and Wales, the Administrative Court reviews the lawfulness of public-body decisions, examining whether the decision-maker acted within legal powers. In the United States, courts review the constitutionality of statutes and the legality of executive action under a written constitution, a power exercised at both federal and state levels. The comparative lesson is practical: the same phrase — 'appeal,' 'review,' 'supreme court' — can mean different things in different systems. Before analyzing any decision, identify the court, its position in the hierarchy, and the type of proceeding, because those facts determine both the binding force of the outcome and the route any further challenge would take.

Common law systems resolve disputes adversarially: the parties investigate, gather evidence, and argue their positions, while the judge — or, in some cases, the jury — acts as a neutral decision-maker rather than an investigator. This contrasts with inquisitorial traditions in some civil law countries, where the judge takes a more active role in developing the case. Adversarial procedure places heavy weight on rules. Rules of evidence determine what the tribunal of fact may hear: relevance, exclusionary principles, and the treatment of hearsay and other categories of proof. Procedural rules govern how a case moves from filing to trial, including pre-trial disclosure — called discovery in the United States — and the framing of issues. England and Wales and the United States share the adversarial heritage, but their procedural regimes are distinct. Each jurisdiction maintains its own civil procedure rules, its own disclosure or discovery standards, and its own appeal routes, so experience in one does not transfer automatically to the other. Jury practice also varies: jury trial is a familiar feature of serious criminal proceedings in both jurisdictions, but its availability in civil cases differs markedly between them. Standards and burdens of proof add another layer, distinguishing criminal from civil matters within each system. The broader point is that procedure is substantive in effect. Whether evidence reaches the decision-maker, how issues are framed, and who bears the burden of proof can determine outcomes as decisively as the underlying legal rules. A comparative lawyer therefore studies procedure with the same seriousness as doctrine.

Equity is the common law world's second stream, and it explains remedies that pure common law could never offer. Historically, when the rigid common law courts produced an inadequate outcome, petitioners petitioned the Lord Chancellor, and a separate court of equity developed principles and remedies of its own. In England and Wales, the administration of law and equity was later merged, but the substantive distinction survives: equitable doctrines and equitable remedies remain a distinct body of law, and equitable relief is discretionary. The classic equitable remedies include the injunction, an order requiring a party to do or refrain from doing something; specific performance, an order to perform a contract rather than merely pay damages; and rescission, which unwinds a transaction. Equitable doctrines — most prominently the trust — remain foundational to property law in both jurisdictions. The United States inherited the same equitable tradition, and courts there likewise grant equitable relief at their discretion, though the availability and shape of particular remedies vary by state and by federal rules. The comparative habit to build is simple: in a common law system, winning is only half the question. The other half is remedy — what the court can actually order. Damages are the ordinary common law response, but where damages are inadequate, equity may reach further, subject always to the court's discretion. That completes the framework of this course: sources, precedent, interpretation, courts, procedure, and equity. Review the chapters, note where the two jurisdictions diverge, and treat this material as education rather than legal advice.