Common law

Precedent is a judicial decision that serves as an authority for courts when deciding subsequent identical or similar cases. Fundamental to common law legal systems, precedent operates under the principle of stare decisis ("to stand by things decided"), where past judicial decisions serve as case law to guide future rulings, thus promoting consistency and predictability.

Precedent is a defining feature that sets common law systems apart from civil law systems. In common law, precedent can either be something courts must follow (binding) or something they can consider but do not have to follow (persuasive). Civil law systems, in contrast, are characterized by comprehensive codes and detailed statutes, with little emphasis on precedent (see, jurisprudence constante), and where judges primarily focus on fact-finding and applying the codified law.

The contemporary national legal systems are generally based on one of four major legal traditions: civil law, common law, customary law, religious law or combinations of these. However, the legal system of each country is shaped by its unique history and so incorporates individual variations. The science that studies law at the level of legal systems is called comparative law.

Both civil (also known as Roman) and common law systems can be considered the most widespread in the world: civil law because it is the most widespread by landmass and by population overall, and common law because it is employed by the greatest number of people compared to any single civil law system.

The adversarial system (also adversary system, accusatorial system, or accusatory system) is a legal system used in the common law countries where two advocates represent their parties' case or position before an impartial person or group of people, usually a judge or jury, who attempt to determine the truth and pass judgment accordingly. It is in contrast to the inquisitorial system used in some civil law systems (i.e. those deriving from Roman law or the Napoleonic Code) where a judge investigates the case.

The adversarial system is the two-sided structure under which criminal trial courts operate, putting the prosecution against the defense.

A barrister is a type of lawyer in common law jurisdictions. Barristers mostly specialise in courtroom advocacy and litigation. Their tasks include arguing cases in courts and tribunals, drafting legal pleadings, researching the law and giving legal opinions.

Barristers are distinguished from solicitors and other types of lawyers (e.g. chartered legal executives) who have more direct access to clients, and may do transactional legal work. In some legal systems, including those of South Africa, Scandinavia, Pakistan, India, Bangladesh, and the Isle of Man, barrister is also regarded as an honorific.

An inquisitorial system is a legal system in which the court, or a part of the court, is actively involved in investigating the facts of the case. This is distinct from an adversarial system, in which the role of the court is primarily that of an impartial referee between the plaintiff or prosecution and the defense.

Inquisitorial systems are used primarily in countries with civil legal systems, such as France and Italy, or legal systems based on Islamic law like Saudi Arabia, rather than in common law systems. It is the prevalent legal system in Continental Europe, Latin America, African countries not formerly under British rule, East Asia (except Hong Kong), Indochina, Thailand, and Indonesia. Most countries with an inquisitorial system also have some form of civil code as their main source of law. Countries using common law, including the United States, may use an inquisitorial system for summary hearings in the case of misdemeanors or infractions, such as minor traffic violations.

In some jurisdictions, an assessor is a judge's or magistrate's assistant. This is the historical meaning of this word.

In common law jurisdictions, assessors are usually non-lawyers who sit together with a judge to provide either expert advice (such as on maritime matters) or guidance on local practices. The use of assessors nowadays is quite rare. In some jurisdictions, such as Fiji, assessors are used in place of juries. An assessor's opinion or view of a case is not binding on a judge.

His Majesty's Attorney General for England and Wales (Welsh: Twrnai Cyffredinol Lloegr a Chymru) is the chief legal adviser to the Sovereign and Government in affairs pertaining to England and Wales as well as the highest ranking amongst the Law officers of the Crown. The Attorney general is the leader of the Attorney General's Office and currently attends (but is not a member of) the Cabinet. Unlike in other countries employing the Common law legal system, the attorney general does not govern the Administration of justice; that function is carried out by the Secretary of State for Justice and Lord Chancellor. The incumbent is also concurrently the Advocate General for Northern Ireland.

The position of Attorney General dates back to at least 1243, when records indicate that a professional attorney was appointed to represent the King's interests in court. The position first took on a political role in 1461 when the holder of the office was summoned to the House of Lords to advise the Government there on legal matters. In 1673, the attorney general officially became the Crown's adviser and representative in legal matters, although still specialising in litigation rather than advice. The beginning of the 20th century saw a shift away from litigation and more towards legal advice. Today, prosecutions are carried out by the Crown Prosecution Service (CPS) and most legal advice to government departments is provided by the Government Legal Department, both under the supervision of the attorney general.

The Constitution of the United States is the supreme law of the United States of America. It superseded the Articles of Confederation, the nation's first constitution, on March 4, 1789. Originally including seven articles, the Constitution defined the foundational structure of the federal government.

The drafting of the Constitution by many of the nation's Founding Fathers, often referred to as its framing, was completed at the Constitutional Convention, which assembled at Independence Hall in Philadelphia between May 25 and September 17, 1787. Influenced by English common law and the Enlightenment liberalism of philosophers like John Locke and Montesquieu, the Constitution's first three articles embody the doctrine of the separation of powers, in which the federal government is divided into the legislative, bicameral Congress; the executive, led by the president; and the judiciary, within which the Supreme Court has apex jurisdiction. Articles IV, V, and VI embody concepts of federalism, describing the rights and responsibilities of state governments, the states in relationship to the federal government, and the process of constitutional amendment. Article VII establishes the procedure used to ratify the constitution.

A privilege is a certain entitlement to immunity granted by the state or another authority to a restricted group, either by birth or on a conditional basis. Land-titles and taxi medallions are examples of transferable privilege – they can be revoked in certain circumstances. In modern democratic states, a privilege is conditional and granted only after birth. By contrast, a right is an inherent, irrevocable entitlement held by all citizens or all human beings from the moment of birth. Various examples of old common law privilege still exist – to title deeds, for example. Etymologically, a privilege (privilegium) means a "private law", or rule relating to a specific individual or institution.

The principles of conduct that members of the legal profession observe in their practice are called legal ethics.

Cruel and unusual punishment is a phrase in common law describing punishment that is considered unacceptable due to the suffering, pain, or humiliation it inflicts on the person subjected to the sanction. The precise definition varies by jurisdiction, but typically includes punishments that are arbitrary, unnecessary, or overly severe compared to the crime.