The common law is created and 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, 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 idealized 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 idealized 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 common law, constitutional 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 consistent principled rules so that they will reach similar results, lies at the heart of all common law systems. This is a broad statement however; in the UK for example, the Practice Statement of 1966 allows the House of Lords, in certain circumstances, to overule a previous decision made in the same House.
Common law legal systems are in widespread use, particularly in those nations which trace their legal heritage to Britain, including the United Kingdom, most of the United States and Canada, and other former colonies of the British Empire.
The term common law has three main connotations and several historical meanings worth mentioning:
For most purposes, most jurisdictions, including the U.S. federal system and most states, have merged the two courts. Additionally, even before the separate courts were merged together, most courts were permitted to apply both law and equity (though under potentially different procedural law). Even so, the split survives and remains relevant for determining many issues in these classes. Other exceptions are discussed in "Common Law Systems," below.
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).
One example of the gradual change that typifies the common law is the gradual change in liability for negligence. For example, the traditional common law rule through most of the 19th century was that a plaintiff could not recover for a defendant's negligence unless the two were in privity of contract. Thus, only the immediate purchaser could recover for a product defect, and if a part was built up out of parts from parts manufacturers, the ultimate buyer could not recover for injury caused by a defect in the part. Winterbottom v. Wright, 10 M&W 109, 152 Eng.Rep. 402, 1842 WL 5519 (Exchequer of pleas 1842). In Winterbottom, the postal service had contracted with Wright to maintain its coaches. Winterbottom was a driver for the post. When the coach failed and injured Winterbottom, he sued Wright. The Winterbottom court recognized that there would be "absurd and outrageous consequences" if an injured person could sue any person peripherally involved, but could not find a good place to draw a line around the causal connection between the negligent conduct and the injury other than to limit liability to only the immediate person in contract with the negligent party. A first exception to this rule arose in Thomas v. Winchester, 6 N.Y. 397 (N.Y. 1852) which held that mislabeling a poison as an innocuous herb, and then selling the mislabeled poison through a dealer who would be expected to resell it, put "human life in imminent danger." Thomas used this as a reason to create an exception to the "privity" rule. In Statler v. Ray Mfg. Co., 195 N.Y. 478, 480 (N.Y. 1909) held that a coffee urn manufacturer was liable to a person injured when the urn exploded, because the urn "was of such a character inherently that, when applied to the purposes for which it was designed, it was liable to become a source of great danger to many people if not carefully and properly constructed."
Yet the privity rule survived. In Cadillac Motor Car Co. v Johnson, 221 F. 801 (2nd Cir. 1915) (decided by the federal appeals court for New York and several neighboring states), the court held that a car owner could not recover for injuries from a defective wheel, when the automobile owner only had a contract with the automobile dealer, not with the manufacturer, even though there was "no question that the wheel was made of dead and ‘dozy‘ wood, quite insufficient for its purposes."
Finally, in the famous case of MacPherson v. Buick Motor Co., 217 N.Y. 382, 111 N.E. 1050 (N.Y. 1916), Judge Cardozo pulled a broader principle out of these predecessor cases. The facts were almost identical to Cadillac a year earlier: a wheel from a wheel manufacturer was sold to Buick, to a dealer, to MacPherson, and the wheel failed, injuring MacPherson. Judge Cardozo held:
Note that Cardozo's new "rule" exists in no prior case, but is inferable as a synthesis of the "thing of danger" principle stated in them, merely extending it to "foreseeable danger" even if "the purposes for which it was designed" were not themselves "a source of great danger." MacPherson takes some care to present itself as foreseeable progression, not a wild departure: note that Judge Cardozo continues to adhere to the original principle of Winterbottom, that "absurd and outrageous consequences" must be avoided, and he does so by drawing a new line in the last sentence quoted above: "There must be knowledge of a danger, not merely possible, but probable." But while adhering to the underlying principle that some boundary is necessary, MacPherson overruled the prior common law by rendering the formerly dominant factor in the boundary, that is, the privity formality arising out of a contractual relationship between persons, totally irrelevant. Rather, the most important factor in the boundary would be the nature of the thing sold and the foreseeable uses that downstream purchasers would make of the thing.
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.
With the transition from English law, which had common law crimes, to the new legal system under the U.S. Constitution, which prohibited ex post facto laws at both the federal and state level, the question was raised whether there could be common law crimes in the United States. It was settled in the case of United States v. Hudson and Goodwin which decided that common law crimes were prohibited (at least at the Federal level), and that there must always be a (constitutional) statute defining the offense and the penalty for it.
However, many states retain selected common law crimes. Virginia, for example, recognizes robbery as a common law crime and the statute referencing robbery as a crime exists to set the punishment. Virginia Code section 1-200 establishes the continued existence and vitality of common law principles and provides that "The common law of England, insofar as it is not repugnant to the principles of the Bill of Rights and Constitution of this Commonwealth, shall continue in full force within the same, and be the rule of decision, except as altered by the General Assembly".
By contrast to statutory codification of common law, some statutes displace common law, for example to create a new cause of action that did not exist in the common law, or to legislatively overrule 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 (cf. judicial activism).
Where a tort is rooted in common law, then all traditionally recognized damages 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.
In the United States, the power of the federal judiciary to review and invalidate unconstitutional acts of the federal executive branch was established in Marbury v. Madison. Later cases extended the "judicial power" of Article III and Marbury to establish the power of federal courts to consider or overturn any unconstitutional action of congress or of any state.
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, policy justification, or the history and evolution of the law, but the court's legal conclusion is reached through analysis of relevant statutes and common law, seldom scholarly commentary.
This is the reason for the frequent choice of the law of the State of New York in commercial contacts. In particular, New York law is often used in contracts throughout the world (for example, in commercial contracts in Japan, France and Germany, and from most of the other states of the United States), and Delaware corporate law is chosen for corporate law issues, even where the relationship of the parties and transaction to New York or Delaware is quite attenuated. Because of its history as the nation's commercial center, New York common law has a depth and predictability not (yet) available in any other jurisdiction. On the other hand, some other jurisdictions have sufficiently developed bodies of law so that parties have no real motivation to choose the law of a foreign jurisdiction (e.g., the United Kingdom and the state of California), but not yet so fully developed that parties with no relationship to the jurisdiction choose that law. The common theme in each case is that commercial parties seek predictability and simplicity in their contractual relations, and frequently choose the law of a common law jurisdiction with a well-developed body of common law in order to achieve that result.
The form of reasoning used in common law is known as casuistry or case-based reasoning. The common law, as applied in civil cases (as distinct from criminal cases), was devised as a means of compensating someone for wrongful acts known as torts, including both intentional torts and torts caused by negligence, and as developing the body of law recognizing and regulating contracts. The type of procedure practiced in common law courts is known as the adversarial system; this is also a development of the common law.
Before the Norman conquest in 1066, justice was administered primarily by county courts, presided by the diocesan bishop and the sheriff, exercising both ecclesiastical and civil jurisdiction. Trial by jury began in these courts.
In 1154, Henry II became the first Plantagenet king. Among many achievements, Henry institutionalized common law by creating a unified system of law "common" to the country through incorporating and elevating local custom to the national, ending local control and peculiarities, eliminating arbitrary remedies and reinstating a jury system – citizens sworn on oath to investigate reliable criminal accusations and civil claims. The jury reached its verdict through evaluating common local knowledge, not necessarily through the presentation of evidence, a distinguishing factor from today's civil and criminal court systems.
Henry II developed the practice of sending judges from his own central court to hear the various disputes throughout the country. His judges would resolve disputes on an ad hoc basis according to what they interpreted the customs to be. The king's judges would then return to London and often discuss their cases and the decisions they made with the other judges. These decisions would be recorded and filed. In time, a rule, known as stare decisis (also commonly known as precedent) developed, which is where a judge would be bound to follow the decision of an earlier judge; he was required to adopt the earlier judge's interpretation of the law and apply the same principles promulgated by that earlier judge if the two cases had similar facts to one another. By this system of precedent, decisions 'stuck' and became ossified, and so the pre-Norman system of disparate local customs was replaced by an elaborate and consistent system of law that was common throughout the whole country, hence the name, "common law."
Henry II's creation of a powerful and unified court system, which curbed somewhat the power of canonical (church) courts, brought him (and England) into conflict with the church, most famously with Thomas Becket, the Archbishop of Canterbury. Eventually, Becket was murdered inside Canterbury Cathedral by four knights who believed themselves to be acting on Henry's behalf. Whether Henry actually intended to bring about the assassination of Becket is doubtful, but there is no question that at the time of the murder, the two men were embroiled in a bitter dispute regarding the power of Royal Courts to exercise jurisdiction over former clergymen. The murder of the Archbishop, who was immediately venerated as a martyr and later as a saint, gave rise to a wave of popular outrage against the King. Henry was forced to repeal the disputed laws and to abandon his efforts to hold church members accountable for secular crimes (see also Constitutions of Clarendon).
In spite of this setback, judge-made common law endured for centuries as the primary source of criminal and civil law throughout the realm. Later, after Parliament acquired legislative powers, statutory law began to limit the scope of the common law in some areas. Even today, however, common law retains its status as an essential element of the British legal system.
Since the publication of legal scholar John Makdisi's "The Islamic Origins of the Common Law" in the North Carolina Law Review, there has been controversy over whether English common law was inspired by medieval Islamic law. Some scholars have argued that several fundamental common law institutions may have been adapted from similar legal institutions in medieval Islamic law and jurisprudence, and introduced to England after the Norman conquest of England by the Normans, who conquered and inherited the Islamic legal administration of the Emirate of Sicily (see Arab-Norman culture). In his 1999 paper, Makdisi drew comparisons between the "royal English contract protected by the action of debt" and the "Islamic Aqd", the "English assize of novel disseisin" and the "Islamic Istihqaq", and the "English jury" and the "Islamic Lafif" in classical Maliki jurisprudence, and argued that these institutions were transmitted to England by the Normans, "through the close connection between the Norman kingdoms of Roger II in Sicily — ruling over a conquered Islamic administration — and Henry II in England. Makdisi also argued that English legal institutions such as "the scholastic method, the license to teach," the "law schools known as Inns of Court" in England (which he asserts are parallel to Madrasas in Islam) and the "European commenda" (parallel to Islamic Qirad) may have also originated from Islamic law. He states that the methodology of legal precedent and reasoning by analogy (Qiyas) are also similar in both the Islamic and common law systems. Makdisi claims these similarities and influences suggest that Islamic law may have laid the foundations for "the common law as an integrated whole".
Other legal scholars such as Monica Gaudiosi, Gamal Moursi Badr and A. Hudson have argued that the English trust and agency institutions in common law, which were introduced by Crusaders, may have been adapted from the Islamic Waqf and Hawala institutions they came across in the Middle East. Dr. Paul Brand also notes parallels between the Waqf and the trusts used to establish Merton College by Walter de Merton, who had connections with the Knights Templar. Brand also points out, however, that the Knights Templar were primarily concerned with fighting the Muslims rather than learning from them, making it less likely that they had knowledge of Muslim legal institutions. It is also worth noting that transferring property to another for the "use" of another developed largely in response to the requirements of feudal inheritance law. Trust law, in particular, is a creature of equity, which derived from the parallel jurisdiction of the Lord Chancellor to decide matters independently to the Royal Courts.
For example, the New York Constitution of 1777 provides that:
[S]uch parts of the common law of England, and of the statute law of England and Great Britain, and of the acts of the legislature of the colony of New York, as together did form the law of the said colony on the 19th day of April, in the year of our Lord one thousand seven hundred and seventy-five, shall be and continue the law of this State, subject to such alterations and provisions as the legislature of this State shall, from time to time, make concerning the same.Alexander Hamilton emphasized in The Federalist that this New York constitutional provision expressly made the common law subject “to such alterations and provisions as the legislature shall from time to time make concerning the same.” Thus, even when reception was effected by a constitution, the common law was still subject to alteration by a legislature's statute.
The Northwest Ordinance, which was approved by the Congress of the Confederation in 1787, guaranteed "judicial proceedings according to the course of the common law." Nathan Dane, the primary author of the Northwest Ordinance, viewed this provision as a default mechanism in the event that federal or territorial statutes were silent about a particular matter; he wrote that if "a statute makes an offence, and is silent as to the mode of trial, it shall be by jury, according to the course of the common law.” In effect, the provision operated as a reception statute, giving legal authority to the established common law in the vast territories where no states had yet been established.
Over time, as new states were formed from federal territories, these territorial reception statutes became obsolete and were re-enacted as state law. For example, a reception statute enacted by legislation in the state of Washington requires that "[t]he common law, so far as it is not inconsistent with the Constitution and laws of the United States, or of the state of Washington nor incompatible with the institutions and condition of society in this state, shall be the rule of decision in all the courts of this state. In this way, the common law was eventually incorporated into the legal systems of every state except Louisiana (which inherited its civil law system from France's Napoleonic Code).
A similar statute exists in Article 8 of the Basic Law of Hong Kong.
In England, courts of law and equity were combined by the Judicature Acts of 1873 and 1875, with equity being supreme in case of conflict.
In the United States, parallel systems of law (providing money damages, with cases heard by a jury upon either party's request) and equity (fashioning a remedy to fit the situation, including injunctive relief, heard by a judge) survived well into the 20th century. The United States federal courts procedurally separated law and equity: the same judges could hear either kind of case, but a given case could only pursue causes in law or in equity, and the two kinds of cases proceeded under different procedural rules. This became problematic when a given case required both money damages and injunctive relief. In 1937, the new Federal Rules of Civil Procedure combined law and equity into one form of action, the "civil action." Fed.R.Civ.P. 2. The distinction survives to the extent that issues that were "common law" as of 1791 (the date of adoption of the Seventh Amendment) are still subject to the right of either party to request a jury, and "equity" issues are decided by a judge.
Alabama, Delaware, Mississippi and New Jersey still have separate courts of law and equity, for example, the Court of Chancery. In many states there are separate divisions for law and equity within one court.
The common law constitutes the basis of the legal systems of: England and Wales, Northern Ireland, Ireland, federal law in the United States, the law of individual U.S. States (except Louisiana), federal law in Canada and the individual Provinces (except Quebec civil law), Australia (both federal and individual states), New Zealand, South Africa, India, Malaysia, Brunei, Pakistan, Singapore, Hong Kong, and many other generally English-speaking countries or Commonwealth countries (except Malta and Scotland). Essentially, every country which has been colonised at some time by England, Great Britain, or the United Kingdom uses common law except those that had been formerly colonised by other nations, such as Quebec (which follows French law to some extent), South Africa and Sri Lanka (which follow Roman Dutch law), where the prior civil law system was retained to respect the civil rights of the local colonists. India's system of common law is also a mixture of English law and the local Hindu law, except in the state of Goa which retains the Portuguese civil code. Nicaragua's legal system also is a mixture of the English Common Law and the Civil Law through the influence of British administration of the Eastern half of the country from the mid-1600s until about 1905, the William Walker period from about 1855 through 1857, USA interventions/occupations during the period from 1909 to 1933, the influence of USA institutions during the Somoza family administrations (1933 through 1979) and the considerable importation between 1979 and the present of USA culture and institutions.
The main alternative to the common law system is the civil law system, which is used in Continental Europe, and most of the rest of the world. The former Soviet Bloc and other Socialist countries used a Socialist law system (some of them use civil law system, for example, Lithuania).
The opposition between civil law and common law legal systems has become increasingly blurred, with the growing importance of jurisprudence (almost like case law but in name) in civil law countries, and the growing importance of statute law and codes in common law countries. An example of this is the United States, where matters of criminal law, commercial law (the Uniform Commercial Code in the early 1960s) and procedure (the Federal Rules of Civil Procedure in the 1930s and the Federal Rules of Evidence in the 1970s) have been codified.
Scotland is often said to use the civil law system but in fact it has a unique system that combines elements of an uncodified civil law dating back to the Corpus Juris Civilis with an element of common law long predating the Treaty of Union with England in 1707 (see Legal institutions of Scotland in the High Middle Ages). Scots common law differs in that the use of precedents is subject to the courts seeking to discover the principle which justifies a law rather than to search for an example as a precedent and that the principles of natural justice and fairness have always formed a source of Scots Law. Comparable pluralistic (or 'mixed') legal systems operate in Quebec, Louisiana and South Africa.
Israel has a mixed system of common law and civil law. While Israeli law is undergoing codification, its basic principles resemble those of British and American law, namely: the role of courts in creating the body of law and the authority of the supreme court in overturning legislative and executive decisions.
The U.S. state of California has a system based on common law, but it has codified the law in the manner of the civil law jurisdictions. The reason for the enactment of the codes in California in the nineteenth century was to replace a pre-existing system based on Spanish civil law with a system based on common law, similar to that in most other states. California and a number of other Western states, however, have retained the concept of community property derived from civil law. The California courts have treated portions of the codes as an extension of the common-law tradition, subject to judicial development in the same manner as judge-made common law. (Most notably, in the case Li v. Yellow Cab Co., 13 Cal.3d 804 (1975), the California Supreme Court adopted the principle of comparative negligence in the face of a California Civil Code provision codifying the traditional common-law doctrine of contributory negligence.)
The state of New York, which also has a civil law history from its Dutch colonial days, also began a codification of its law in the 19th century. The only part of this codification process that was considered complete is known as the Field Code applying to civil procedure. The original colony of New Netherlands was settled by the Dutch and the law was also Dutch. When the English captured pre-existing colonies they continued to allow the local settlers to keep their civil law. However, the Dutch settlers revolted against the English and the colony was recaptured by the Dutch. When the English finally regained control of New Netherland they forced, as a punishment unique in the history of the British Empire, the English common law upon all the colonists, including the Dutch. This was problematic, as the patroonsystem of land holding, based on the feudal system and civil law, continued to operate in the colony until it was abolished in the mid-nineteenth century. The influence of Roman Dutch law continued in the colony well into the late nineteenth century. The codification of a law of general obligations shows how remnants of the civil law tradition in New York continued on from the Dutch days.
The United States federal government (as opposed to the states) has a variant on a common law system. United States federal courts only act as interpreters of statutes and the constitution (to elaborate and precisely define the broad language, connotation 1(b) above), but, unlike state courts, do not act as an independent source of common law (connotation 1(a) above). Before 1938, the federal courts, like almost all other common law courts, decided the law on any issue where the relevant legislature (either the U.S. Congress or state legislature, depending on the issue), had not acted, by looking to courts in the same system, that is, other federal courts, even on issues of state law, and even where there was no express grant of authority from Congress or the Constitution. In 1938, the U.S. Supreme Court in Erie Railroad Co. v. Tompkins 304 U.S. 64, 78 (1938), overruled earlier precedent, and held "There is no federal general common law," thus confining the federal courts to act only as interpreters of law originating elsewhere. E.g., Texas Industries v. Radcliff, (without an express grant of statutory authority, federal courts cannot create rules of intuitive justice, for example, a right to contribution from co-conspirators). Post-1938, federal courts deciding issues that arise under state law are required to defer to state court interpretations of state statutes, or reason what a state's highest court would rule if presented with the issue, or to certify the question to the state's highest court for resolution. Later courts have limited Erie slightly, to create a few situations where United States federal courts are permitted to create federal common law rules without express statutory authority, for example, where a federal rule of decision is necessary to protect uniquely federal interests. See, e.g., Clearfield Trust Co. v. United States, (giving federal courts the authority to fashion common law rules with respect to issues of federal power, in this case negotiable instruments backed by the federal government); see also International News Service v. Associated Press, 248 U.S. 215 (1918) (creating a cause of action for misappropriation of "hot news" that lacks any statutory grounding, but that is one of the handful of federal common law actions that survives today). Except on Constitutional issues, Congress is free to legislatively overrule federal courts' common law.
The definitive historical treatise on the common law is Commentaries on the Laws of England, written by Sir William Blackstone and first published in 1765 - 1769. Since 1979 a facsimile edition of that first edition has been available in four paper-bound volumes. Today it has been superseded in the English part of the United Kingdom by Halsbury's Laws of England that covers both common and statutory English law.
While he was still on the Massachusetts Supreme Judicial Court, and before being named to the U.S. Supreme Court, Justice Oliver Wendell Holmes Jr. published a short volume called The Common Law which remains a classic in the field. Unlike Blackstone and the Restatements, Holmes' book only briefly discusses what the law is; rather, Holmes describes the common law process. Law professor John Chipman Gray's The Nature and Sources of the Law, an examination and survey of the common law, is also still commonly read in U.S. law schools.
In the United States, Restatements of various subject matter areas (Contracts, Torts, Judgments, etc.), edited by the American Law Institute, collect the common law for the area. The ALI Restatements are often cited by American courts and lawyers for propositions of uncodified common law, and are considered highly-persuasive authority, just below binding precedential decisions. The Corpus Juris Secundum is an encyclopedia whose main content is a compendium of the common law and its variations throughout the various state jurisdictions.
Scots common law covers matters including murder and theft, and has sources in custom, in legal writings and previous court decisions. The legal writings used are called Institutional Texts and come mostly from the 17th, 18th and 19th centuries. Examples include Craig, Jus Feudale (1655) and Stair, The Institutions of the Law of Scotland (1681).