Legal Capacity

Legal capacity is a foundational concept in both domestic and international law. It distinguishes between legal personality (being recognized as a subject of law capable of holding rights and duties) and the capacity to act (the power to exercise those rights through valid legal acts, such as signing contracts, marrying, or initiating litigation). A newborn child, for example, has legal personality but lacks full capacity to act until reaching the age of majority set by national law.

In private law, capacity is typically tied to age, mental competence, and absence of judicial restrictions (e.g., guardianship orders). Civil codes in the Romano-Germanic tradition, such as the French Code civil and the German BGB, distinguish capacité de jouissance from capacité d'exercice. Common law jurisdictions reach similar results through doctrines of infancy, mental incapacity, and intoxication that render contracts voidable.

In international law, legal capacity attaches to subjects such as states, intergovernmental organizations, and, in limited respects, individuals and corporations. States possess plenary capacity under customary international law, including the ability to conclude treaties (codified in the Vienna Convention on the Law of Treaties, 1969, Article 6: "Every State possesses capacity to conclude treaties"). International organizations have functional capacity limited by their constituent instruments, a principle affirmed by the ICJ in the Reparation for Injuries advisory opinion (1949), which recognized the UN's capacity to bring international claims.

A major modern development is Article 12 of the Convention on the Rights of Persons with Disabilities (CRPD, 2006), which requires states to recognize that persons with disabilities enjoy legal capacity on an equal basis with others. The CRPD Committee's General Comment No. 1 (2014) interprets this as requiring states to replace substituted decision-making regimes with supported decision-making, a position that has prompted significant guardianship law reforms in jurisdictions including Peru, Costa Rica, and Colombia.