The judiciary is the system of courts and judges responsible for resolving legal disputes and interpreting and applying law. The term can refer both to judicial institutions and collectively to their officeholders. Within a government, the judiciary exercises powers assigned by the constitution and other legal rules. Its functions include determining facts, deciding legal rights and obligations, and reviewing public action where authorized. Its institutional position, jurisdiction, and relationship with other public authorities differ among legal systems. (en.wikipedia.org)
Functions and jurisdiction
Adjudication involves determining a dispute through legally prescribed procedures. Trial courts establish relevant facts and apply legal rules to them. Their authority, known as jurisdiction, determines which disputes they may hear. In the United States, for example, federal and state courts have different jurisdictions: state courts handle most criminal cases and many matters involving contracts, family relationships, and estates, while federal courts hear categories established by federal constitutional and statutory law. (uscourts.gov)
Judicial work encompasses several fields. Civil proceedings determine rights and obligations and may result in compensation, injunctions, or declarations of legal rights. Criminal proceedings determine whether an accused person committed an offence and, following conviction, may lead to sentencing. Administrative law concerns public administration and provides a framework for challenges to official decisions. These functions need not be exercised by the same courts or through identical procedures. (uscourts.gov)
Courts also interpret legislation. In common-law systems, judicial decisions develop rules through precedent, alongside statutes. In England and Wales, a judge deciding a case must follow applicable precedents established by higher courts. Judicial interpretation therefore does more than mechanically repeat legislative language: it determines how legal rules apply to particular circumstances. (judiciary.uk)
Institutional organization
Many judicial systems distinguish between trial courts, appellate courts, and a court of final appeal. Trial courts primarily hear evidence and decide cases initially. Appellate courts review challenged decisions for legal or procedural error. In the United States federal system, appeals generally proceed on the existing record rather than through a new trial with witnesses; appellate courts may affirm, reverse, or return a case for further proceedings. (uscourts.gov)
Specialized courts may deal with bankruptcy, taxation, family matters, or other defined subjects. Federalism can produce parallel national and constituent-state court systems rather than a single unified hierarchy. In the United States, state courts are not simply lower federal courts, although certain questions of federal law decided by state courts can ultimately reach the United States Supreme Court. (uscourts.gov)
Some systems assign constitutional questions to a specialized constitutional court. Germany’s Federal Constitutional Court, for example, hears constitutional complaints and disputes concerning constitutional powers. If an ordinary court considers a relevant statute unconstitutional, it must refer that question to the Constitutional Court rather than itself declare the statute void. (bundesverfassungsgericht.de)
Separation of powers and judicial review
Under separation of powers, judicial functions are institutionally distinguished from those of the legislature and executive. Separation does not mean complete administrative isolation: legislation defines many judicial powers, public authorities provide resources, and courts may depend on executive institutions to enforce decisions. The United States constitutional arrangement combines distinct branches with checks and balances. (uscourts.gov)
Judicial review allows courts, within their jurisdiction, to examine the legality of public action. Its scope varies. In England and Wales, review of administrative decisions concerns lawfulness rather than simply substituting the court’s preferred policy outcome. Constitutional review can also concern legislation: Germany’s Constitutional Court determines whether statutes comply with the Basic Law. Neither function amounts to a general power to decide political expediency. (judiciary.uk)
Institutional separation has developed historically rather than following one universal pattern. The British House of Lords formerly exercised final appellate functions while also being a legislative chamber. Those judicial powers transferred to the separate Supreme Court of the United Kingdom on October 1, 2009. (parliament.uk)
Independence and accountability
Judicial independence means that judicial decisions should be made according to law and evidence without improper pressure. It concerns both individual judges and the judiciary institutionally. Impartiality is related but distinct: judges must approach parties and issues without bias. These principles underpin the rule of law and protection of human rights. (judiciary.uk)
The United Nations Basic Principles on the Independence of the Judiciary call for constitutional or legal guarantees of independence, adequate resources, qualified judicial selection, and legally secured conditions of service. They also provide standards for disciplinary proceedings and removal. Independence therefore coexists with accountability under established procedures; it does not exempt judges from professional responsibilities. (unodc.org)
Proceedings and fair-trial guarantees
Judicial proceedings regulate the presentation of evidence, legal argument, and decisions. In a jury trial, judges explain the applicable law while jurors determine factual questions; in a bench trial, the judge performs both roles. In United States federal criminal trials, the prosecution bears the burden of proof beyond reasonable doubt, whereas civil liability generally requires a preponderance of evidence. (uscourts.gov)
Article 14 of the International Covenant on Civil and Political Rights establishes equality before courts and a right to a fair hearing by a competent, independent, impartial tribunal established by law. It also recognizes the presumption of innocence and specified criminal procedural guarantees, including defence rights and review of conviction and sentence by a higher tribunal. (2covenants.ohchr.org)
International judicial institutions
Judicial institutions also operate beyond national systems. The International Court of Justice, the principal judicial organ of the United Nations, applies international law to disputes submitted by states and gives advisory opinions requested by authorized bodies. Only states may be parties to its contentious cases, and its jurisdiction depends on their consent. It is not a general appellate court for national judgments. (icj-cij.org)