Courts

What do courts do?

Courts resolve disputes, test the state’s case against individuals, interpret law, and review public decisions. This guide explains those functions and why judicial independence is structural.

Fact-checkedLast updated 23 July 2026Last reviewed 23 July 2026

In short

A court is a body with legal authority to decide disputes and to determine the consequences of its decisions. It applies law to established facts and gives reasons that can be examined afterwards.

Courts perform four distinguishable functions: resolving disputes between private parties, deciding criminal cases brought by the state, reviewing decisions made by public bodies, and interpreting what the law means for cases that follow.

Why it exists

Two problems make courts necessary. First, disputes need an authoritative ending — a decision the parties are required to accept even when one of them disagrees with it. Second, the state needs to be capable of being told that it is wrong, by a body it does not control.

The second function is the harder one to build, because the institution that must be constrained is also the institution that funds, appoints, and can in principle abolish the constraint. Almost every structural feature of a judiciary — appointment procedure, security of tenure, protected pay, immunity for judicial acts, published reasoning — is an answer to that problem.

International instruments treat independent adjudication as a requirement rather than a preference. The International Covenant on Civil and Political Rights provides in Article 14 for a fair and public hearing by a competent, independent and impartial tribunal established by law, and the Universal Declaration expresses the same principle.

How it works

Establishing facts: Deciding what happened, on admissible evidence, to the standard the type of case requires. Criminal cases require a higher standard than civil disputes.
Applying law to those facts: Determining what the applicable rules require in the situation found. Where the law is unclear, the court decides what it means.
Giving reasons: Explaining the basis of the decision, which is what allows it to be challenged, criticised, and relied on in later cases.
Determining consequences: Sentence, remedy, order, or compensation, within limits set by law.
Reviewing other public decisions: Deciding whether a public body acted within its powers and followed a lawful process — a question about legality rather than about whether the decision was wise.

Court systems are arranged in hierarchies. First-instance courts hear cases initially and establish the facts. Appellate courts review for legal error or procedural unfairness. A supreme or constitutional court sits at the top, usually hearing a small number of cases that raise questions of general importance.

International courts operate alongside national ones with defined and limited jurisdiction. The International Criminal Court, established by the Rome Statute of 1998, is complementary to national jurisdictions rather than superior to them — it acts where national systems are unwilling or unable to do so, and only in respect of the crimes and states within its jurisdiction.

Common misconceptions

Widely held beliefs that do not match how the system actually operates.

Common belief: Courts exist mainly to try criminal cases.
In practice: Civil disputes, family matters, employment claims, and administrative review occupy most courts most of the time. Criminal trials are the most visible part of the work rather than the largest.
Common belief: A trial establishes what really happened.
In practice: A criminal trial decides whether the case brought meets the required standard on the admissible evidence. That is a narrower question than "what happened", and the difference explains outcomes that look inexplicable from outside — including acquittals in cases where a court has not concluded that nothing occurred.
Common belief: An appeal is a fresh hearing.
In practice: In most systems appellate courts review for legal error or procedural unfairness rather than re-deciding the facts, and are reluctant to disturb findings made by the court that saw the witnesses. Some systems do provide full rehearing at the first appellate level; which applies is a national question.
Common belief: Judges make the law they apply.
In practice: Judges interpret law and, in common-law systems, develop it incrementally through decisions that bind later courts. Both are constrained activities: legislation prevails over judicial interpretation, and reasoning must be published and defensible. The scope of judicial development varies substantially between legal traditions.

How this varies between jurisdictions

A required section on every guide. Arrangements differ between countries, and we say how.

Who decides the facts differs: a professional judge alone, a panel of professional judges, a jury of citizens, or a mixed panel of professional and lay judges sitting together.
Adversarial systems leave the parties to build and present the case; inquisitorial systems give the court a stronger investigative role. Most systems mix elements, and the mix has moved in both directions over time.
Constitutional review may sit with a single specialised court, with all courts, or be unavailable against primary legislation.
Administrative decisions may be reviewed by ordinary courts or by a separate hierarchy of administrative courts.
The role of prior decisions differs: binding precedent in common-law systems, persuasive but formally non-binding in many civil-law systems, with the practical gap between the two often narrower than the doctrine suggests.

Rights and accountability

Courts are simultaneously an accountability mechanism for other institutions and a body that must itself be accountable. That dual position shapes how their accountability is designed: it must be real without allowing decisions to be punished.

Hearings are generally public, and judgments are generally published, so reasoning is open to scrutiny.
Decisions are subject to appeal, which is the primary corrective for a wrong decision.
Judicial conduct — as distinct from the merits of decisions — is examined by judicial councils, specialised tribunals, or parliamentary procedures depending on the system.
Security of tenure exists so that a judge cannot be removed for deciding against the government. It is a protection for the public rather than a privilege for the judge.

Where to go next

This guide explains what courts do. How court systems are STRUCTURED, and how much they differ, is covered by court hierarchy, why courts matter and why judicial independence matters. Related: due process, what a prosecutor does, why hearings are public, and the rule of law. For a court system built on almost none of the components this page assumes, see how Athenian courts worked.

Why do courts matter — to public order, and to individual liberty?
Courts settle disputes without force, test accusations before they count, and measure the state’s own acts against law. They matter to order and to liberty for the same reason: a decision no one can review is not a decision anyone has to justify.
How are court systems structured — and is every system one pyramid?
Most descriptions show a single pyramid rising to one supreme court. Six of the twelve systems examined here have more than one hierarchy, and what usually decides the route is the nature of the dispute rather than its seriousness.
What arrangements make a judiciary independent, and does having them mean it is?
Independence is built from appointment, tenure, pay, administration and the separation of governing bodies from adjudicating ones. Every one of those is a formal guarantee, and a formal guarantee is not the same as a working one.
What is due process?
Due process is the requirement that the state follow fair, established procedures before it takes action against a person. This guide explains what it typically includes and how it differs between systems.
What does a prosecutor do?
A prosecutor decides whether a criminal case should be brought, on what charges, and presents it in court. This guide explains the tests applied, the duties owed, and how the role differs between systems.
What is the rule of law?
The rule of law is the principle that everyone, including the government, is subject to law that is public, applied equally, and interpreted by independent courts. This guide explains what it requires and what it does not.

Sources

International Covenant on Civil and Political Rights (United Nations Treaty Series, vol. 999, No. I-14668)
United Nations · International organisation · 1966 · link verified 2026-07-23
Authentic treaty text as registered in the UN Treaty Series; registered ex officio 23 March 1976. Supports the fair-trial guarantees of Article 14, including the right to a competent, independent and impartial tribunal established by law, and the presumption of innocence (Art. 14(2)). Binding only on states party to it; does not support claims about states that have not ratified, nor about how any individual state applies it. WAVE 19 ADDITION, read from the same authentic treaty text in the UN Treaty Series PDF, text-extracted locally. Supports Article 14(5) in full: "Everyone convicted of a crime shall have the right to his conviction and sentence being reviewed by a higher tribunal according to law." The qualifier "according to law" is part of the provision and is load-bearing: the right is to review as the law of the state provides, not to appeal without limit or by any chosen route. Supports Article 14(6): where a person has by a FINAL decision been convicted of a criminal offence and the conviction has subsequently been reversed or the person pardoned on the ground that a new or newly discovered fact shows conclusively that there has been a miscarriage of justice, the person who has suffered punishment as a result shall be compensated according to law, unless it is proved that the non-disclosure of the unknown fact in time is wholly or partly attributable to that person. Supports Article 14(3)(g), that no one shall be compelled to testify against himself or to confess guilt, and Article 14(4), that the procedure for juvenile persons shall take account of their age and the desirability of promoting their rehabilitation. WAVE 20 ADDITION. PROVENANCE, stated precisely because this record's url is a different copy: the Article 4 material below was read on 2026-08-26 from OHCHR's official PDF of the Covenant at https://www.ohchr.org/sites/default/files/ccpr.pdf. The United Nations Treaty Series copy at this record's url timed out repeatedly this session and was not re-read, so nothing in this addition rests on it. Article 4 is the derogation clause, and its four cumulative conditions are the point. Supports ICCPR Art. 4(1): “1. In time of public emergency which threatens the life of the nation and the existence of which is officially proclaimed, the States Parties to the present Covenant may take measures derogating from their obligations under the present Covenant to the extent strictly required by the exigencies of the situation, provided that such measures are not inconsistent with their other obligations under international law and do not involve discrimination solely on the ground of race, colour, sex, language, religion or social origin.”. Supports ICCPR Art. 4(2), read with Arts. 6, 7, 8, 11, 15, 16 and 18 as printed in the same document: “2. No derogation from articles 6, 7, 8 (paragraphs 1 and 2), 11, 15, 16 and 18 may be made under this provision.”. Supports ICCPR Art. 4(3): “3. Any State Party to the present Covenant availing itself of the right of derogation shall immediately inform the other States Parties to the present Covenant, through the intermediary of the Secretary-General of the United Nations, of the provisions from which it has derogated and of the reasons by which it was actuated. A further communication shall be made, through the same intermediary, on the date on which it terminates such derogation.”. The Covenant binds States Parties to it. It is NOT evidence of any particular state's domestic law, and no country claim on this platform rests on it. It designates no organ to proclaim an emergency, assigns no role to any national legislature, and creates no civil-protection institution. The Human Rights Committee's interpretation of this article is cited separately and attributed to the Committee.WAVE 21 ADDITION. Read from the same United Nations Treaty Series PDF, text-extracted and searched. Supports Art. 9(1)-(4), and specifically that the Covenant polices ARBITRARINESS rather than closing a list of grounds: “Everyone has the right to liberty and security of person. No one shall be subjected to arbitrary arrest or detention. No one shall be deprived of his liberty except on such grounds and in accordance with such procedure as are established by law”; with 9(2) (informed at the time of arrest of the reasons and promptly of any charges), 9(3) (brought promptly before a judge or other officer authorised by law to exercise judicial power; it shall not be the general rule that persons awaiting trial shall be detained in custody) and 9(4) (entitlement to take proceedings before a court which decides without delay on the lawfulness of the detention). Supports Art. 14(1): “All persons shall be equal before the courts and tribunals”, with the right to a fair and public hearing by a competent, independent and impartial tribunal established by law, the closed grounds on which press and public may be excluded, and the rule that judgment shall be made public except where the interest of juvenile persons otherwise requires or the proceedings concern matrimonial disputes or the guardianship of children. Supports Art. 14(3)(e) (“To examine, or have examined, the witnesses against him and to obtain the attendance and examination of witnesses on his behalf under the same conditions as witnesses against him”), 14(3)(f) (free assistance of an interpreter) and 14(3)(g) (“Not to be compelled to testify against himself or to confess guilt” — note that the Covenant adds the confession limb, which the European Convention text does not contain). Supports Art. 14(5). VERIFIED NEGATIVES from exhaustive search of the Covenant text: “proportion” occurs zero times, “equality of arms” zero times, and “remain silent” zero times. This is treaty text binding states party to it; it is not evidence of any state's domestic law, and the corpus invariant forbidding a treaty from standing in for a country applies to it.
Universal Declaration of Human Rights
United Nations · International organisation · 1948-12-10 · link verified 2026-07-23
Supports the existence and wording of the declared principles of equality before the law (Art. 7), the right to an effective remedy (Art. 8), the right to a fair and public hearing by an independent and impartial tribunal (Art. 10), and the presumption of innocence (Art. 11). A declaration, not a treaty: it does not establish binding obligations, and it does not support any claim about how a particular state implements these principles.
Rome Statute of the International Criminal Court, 1998
United Nations (Office of Legal Affairs) · International organisation · 1998 · link verified 2026-07-23
Supports the existence, constitution, and jurisdictional limits of the International Criminal Court, including its complementarity to national jurisdictions. Does not support claims about the Court's effectiveness or about states that are not party to it.