Guide To Understanding
In common law legal systems, the law is created and/or refined by judges: a decision in the case currently pending depends on decisions in previous cases and affects the law to be applied in future cases. When there is no authoritative statement of the law, common law judges have the authority and duty to "make" law by creating precedent. The body of precedent is called "common law" and it binds future decisions. In future cases, when parties disagree on what the law is, an "ideal" common law court looks to past precedential decisions of relevant courts. If a similar dispute has been resolved in the past, the court is bound to follow the reasoning used in the prior decision (this principle is known as stare decisis). If, however, the court finds that the current dispute is fundamentally distinct from all previous cases, it will decide as a "matter of first impression." Thereafter, the new decision becomes precedent, and will bind future courts under the principle of stare decisis.
In practice, common law systems are considerably more complicated than the "ideal" system described above. The decisions of a court are binding only in a particular jurisdiction, and even within a given jurisdiction, some courts have more power than others. For example, in most jurisdictions, decisions by appellate courts are binding on lower courts in the same jurisdiction and on future decisions of the same appellate court, but decisions of non-appellate courts are only non-binding persuasive authority. Interactions between constitutional law, common law, statutory law and regulatory law also give rise to considerable complexity. However, stare decisis, the principle that similar cases should be decided according to similar rules, lies at the heart of all common law systems.
Common law legal systems are in widespread use, particularly in those nations which trace their legal heritage to England, including the United Kingdom, the United States, most of Canada, and other former colonies of the British Empire.
There are three main connotations for to the term common law, and several historical ones worth mentioning:
1. Common law as opposed to statutory law and regulatory law: This connotation distinguishes the authority that promulgated a law. For example, in most areas of law in most jurisdictions in the United States, there are "statutes" enacted by a legislature, "regulations" promulgated by executive branch agencies pursuant to a delegation of rule-making authority from a legislature, and common law or "case law", i.e. decisions issued by courts (or quasi-judicial tribunals within agencies). This first connotation can be further differentiated, into (a) laws that arise purely from the common law with no express statutory authority, e.g. most criminal law and procedural law before the 20th century, and even today, most of contract law and the law of torts, and (b) decisions that discuss and decide the fine boundaries and distinctions in written laws promulgated by other bodies, such as the Constitution, statutes and regulations.
2. Common law legal systems as opposed to civil law legal systems: This connotation differentiates "common law" jurisdictions and legal systems from "civil law" or "code" jurisdictions. Common law systems place great weight on court decisions, which are considered "law" just as are statutes. By contrast, in civil law jurisdictions (the legal tradition that prevails in most of the world), judicial precedent is given less weight, and contributions by scholars are given more. For example, the Napoleonic code expressly forbade French judges from pronouncing the law.
3. Law as opposed to equity: This connotation differentiates "common law" (or just "law") from "equity". Before 1873, England had two parallel court systems, courts of "law" that could only award money damages and recognized only the legal owner of property, and courts of "equity" that could issue injunctive relief and recognized trusts of property. Most United States jurisdictions have merged the two courts, with exceptions noted in "Common Law Systems," below. Additionally, even before the separate courts were merged together, most courts were permitted to apply both law and equity (though under potentially different laws of procedure). Even so, the distinction between law and equity remains important in (a) categorising and prioritizing rights to property, (b) determining whether the Seventh Amendment's right to a jury trial applies (a determination of a fact necessary to resolution of a "common law" claim) or whether the issue may be decided by a judge (issues of what the law is, and all issues relating to equity), and (c) in the principles that apply to the grant of equitable remedies by the courts.
4. Historical uses: In addition, there are several historical uses of the term that provide some background as to its meaning. The English Court of Common Pleas dealt with lawsuits in which the king had no interest, i.e. between commoners. Additionally, from at least the 11th century and continuing for several centuries after that, there were several different circuits in the royal court system, served by itinerant judges who would travel from town to town dispensing the King's justice. The term "common law" was used to describe the law held in common between the circuits and the different stops in each circuit. The more widely a particular law was recognized, the more weight it held, whereas purely local customs were generally subordinate to law recognized in a plurality of jurisdictions. These definitions are archaic, their relevance having dissipated with the development of the English legal system over the centuries, but they do explain the origin of the term.
Basic Principles of Common Law
Common Law Adjudication
In a common law jurisdiction, several stages of research and analysis are required to determine what "the law is" in a given situation. First, one must ascertain the facts. Then, one must locate any relevant statutes and cases. Then one must extract the principles, analogies and statements by various courts of what they consider important to determine how the next court is likely to rule on the facts of the present case. Later decisions, and decisions of higher courts or legislatures carry more weight than earlier cases and those of lower courts. Finally, one integrates all the lines drawn and reasons given, and determines what "the law is". Then, one applies that law to the facts.
The common law is more malleable than statutory law. First, common law courts are not absolutely bound by precedent, but can (when extraordinarily good reason is shown) reinterpret and revise the law, without legislative intervention, to adapt to new trends in political, legal and social philosophy. Second, the common law evolves through a series of gradual steps, that gradually works out all the details, so that over a decade or more, the law can change substantially but without a sharp break, thereby reducing disruptive effects. In contrast, the legislative process is very difficult to get started: legislatures do not act until a situation is totally intolerable. Because of this, legislative changes tend to be large, jarring and disruptive (either positively or negatively).
Interaction of Statute and Common Law
In common law legal systems (connotation 2), the common law (connotation 1) is crucial to understanding almost all important areas of law. For example, in England and Wales and in most states of the United States, the basic laws of contracts, torts and property do not exist in statute, but only in common law (though there may be isolated modifications enacted by statute). In almost all areas of the law (even those where there is a statutory framework, such as contracts for the sale of goods, or the criminal law), other written laws generally give only terse statements of general principle, and the fine boundaries and definitions exist only in the common law (connotation 1). To find out what the precise law is that applies to a particular set of facts, one has to locate precedential decisions on the topic, and reason from those decisions by analogy. To consider but one example, the First Amendment to the United States Constitution states "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof" – but interpretation (that is, determining the fine boundaries, and resolving the tension between the "establishment" and "free exercise" clauses) of each of the important terms was delegated by Article III of the Constitution to the judicial branch, so that the current legal boundaries of the Constitutional text can only be determined by consulting the common law.
In common law jurisdictions, legislatures operate under the assumption that statutes will be interpreted against the backdrop of the pre-existing common law case law and custom, and so may leave a number of things unsaid. For example, in most U.S. states, the criminal statutes are primarily codification of pre-existing common law. (Codification is the process of enacting a statute that collects and restates pre-existing law in a single document - when that pre-existing law is common law, the common law remains relevant to the interpretation of these statutes.) In reliance on this assumption, modern statutes often leave a number of terms and fine distinctions unstated -- for example, a statute might be very brief, leaving the precise definition of terms unstated, under the assumption that these fine distinctions will be inherited from pre-existing common law. For this reason, even today American law schools teach the common law of crime as practised in England in 1789, because the backdrop of centuries-old English common law is necessary to interpret and fully understand the literal words of the modern criminal statute.
By contrast to the statutory codifications of common law, some laws are purely statutory, and may create a new cause of action beyond the common law. An example is the tort of wrongful death, which allows certain persons, usually a spouse, child or estate, to sue for damages on behalf of the deceased. There is no such tort in English common law; thus, any jurisdiction that lacks a wrongful death statute will not allow a lawsuit for the wrongful death of a loved one. Where a wrongful death statute exists, the compensation or other remedy available is limited to the remedy specified in the statute (typically, an upper limit on the amount of damages). Courts generally interpret statutes that create new causes of action narrowly – that is, limited to their precise terms – because the courts generally recognize the legislature as being supreme in deciding the reach of judge-made law unless such statute should violate some "second order" constitutional law provision (compare judicial activism).
Where a tort is rooted in common law, then all damages traditionally recognized historically for that tort may be sued for, whether or not there is mention of those damages in the current statutory law. For instance, a person who sustains bodily injury through the negligence of another may sue for medical costs, pain, suffering, loss of earnings or earning capacity, mental and/or emotional distress, loss of quality of life, disfigurement and more. These damages need not be set forth in statute as they already exist in the tradition of common law. However, without a wrongful death statute, most of them are extinguished upon death.
The role of treatises and academic writings — one of several contrasts between common law and civil law
In many subject matter areas, legal treatises compile common law decisions and state overarching principles that, in the author's opinion, explain the results of the cases. However, treatises are not the law, and lawyers and judges tend to use these treatises as only "finding aids" to locate the relevant cases.
This is one of the "cultural" differences between common law and civil law jurisdictions (connotation 2): in civil law jurisdictions, the writings of law professors are given significant weight by courts. In common law jurisdictions, scholarly work is seldom cited as authority for what the law is. When common law courts rely on scholarly work, it is almost always only for factual findings or for policy justification, but the court's legal conclusion is reached through analysis of relevant statutes and common law, seldom scholarly commentary.
Common Law as a Foundation
For Commercial Economies
This reliance on judicial opinion is a strength of common law systems, and is a significant contributor to the robust commercial systems in the United Kingdom and United States. Because there is common law to give reasonably precise guidance on almost every issue, parties (especially commercial parties) can predict whether a proposed course of action is likely to be lawful or unlawful. This ability to predict gives more freedom to come close to the boundaries of the law. For example, many commercial contracts are more economically efficient, and create greater wealth, because the parties know ahead of time that the proposed arrangement, perhaps close to the line, is almost certainly legal. Newspapers, taxpayer-funded entities with some religious affiliation, and political parties can obtain fairly clear guidance on the boundaries within which their freedom of expression rights apply. In contrast, in non-common-law countries, fine questions of law are redetermined anew each time they arise, making consistency and prediction more difficult. Thus, in jurisdictions that do not have a strong allegiance to a large body of precedent, parties have less a priori guidance must often leave a bigger "safety margin" of unexploited opportunities.