Legal capacity is a quality denoting either the legal aptitude of a person to have rights and liabilities (in this sense also called transaction capacity), or the personhood itself in regard to an entity other than a natural person (in this sense also called legal personality).
Natural persons
Capacity covers day-to-day decisions, including: what to wear and what to buy, as well as, life-changing decisions, such as: whether to move into a care home or whether to have major surgery.
As an aspect of the social contract between a state and its citizens, the state adopts a role of protector to the weaker and more vulnerable members of society. In public policy terms, this is the policy of parens patriae. Similarly, the state has a direct social and economic interest in promoting trade, so it will define the forms of business enterprise that may operate within its territory and lay down rules that will allow both the businesses and those that wish to contract with them a fair opportunity to gain value. This system worked well until social and commercial mobility increased. Now persons routinely trade and travel across state boundaries (both physically and electronically), so the need is to provide stability across state lines given that laws differ from one state to the next. Thus, once defined by the personal law, persons take their capacity with them like a passport whether or however they may travel. In this way, a person will not gain or lose capacity depending on the accident of the local laws, e.g. if A does not have capacity to marry her cousin under her personal law (a rule of consanguinity), she cannot evade that law by travelling to a state that does permit such a marriage (see nullity). In Saskatchewan Canada, an exception to this law allows married persons to become the common law spouse of other(s) prior to divorcing the first spouse. This law is not honored amongst other Canadian provinces.
Legal capacity
Standardized classes of person have had their freedom restricted. These limitations are exceptions to the general policy of freedom of contract and the detailed human and civil rights that a person of ordinary capacity might enjoy. For example, freedom of movement may be modified, the right to vote may be withdrawn, etc. As societies have developed more equal treatment based on gender, race and ethnicity, many of the older incapacities have been removed. For example, English law used to treat married women as lacking the capacity to own property or act independently of their husbands (the last of these rules was repealed by the Domicile and Matrimonial Proceedings Act 1973, which removed the wife's domicile of dependency for those marrying after 1974, so that a husband and wife could have different domiciles).
Minors
The definition of an infant or minor varies, each state reflecting local culture and prejudices in defining the age of majority, marriageable age, voting age, etc. In many jurisdictions, legal contracts, in which (at least) one of the contracting parties is a minor, are voidable by the minor. For a minor to undergo medical procedure, consent is determined by the minor's parent(s) or legal guardian(s). The right to vote in the United States is currently set at 18 years, while the right to buy and consume alcohol is often set at 21 years by U.S. state law. Some laws, such as marriage laws, may differentiate between the sexes and allow women to marry at a younger age. There are instances in which a person may be able to gain capacity earlier than the prescribed time through a process of emancipation. Conversely, many states allow the inexperience of childhood to be an excusing condition to criminal liability and set the age of criminal responsibility to match the local experience of emerging behavioral problems (see doli incapax). For sexual crimes, the age of consent determines the potential liability of adult accused.
As an example of liability in contract, the law in most of Canada provides that an infant is not bound by the contracts he or she enters into except for the purchase of necessaries and for beneficial contracts of service. Infants must pay fair price only for necessary goods and services. However, the British Columbia Infants Act ( 1996 c.223) declares all contracts, including necessities and beneficial contracts of service, are unenforceable against an infant. Only student loans and other contracts made specifically enforceable by statute will be binding on infants in that province.
In contracts between an adult and an infant, adults are bound but infants may escape contracts at their option (i.e. the contract is voidable). Infants may ratify a contract on reaching age of majority. In the case of executed contracts, when the infant has obtained some benefit under the contract, he/she cannot avoid obligations unless what was obtained was of no value. Upon repudiation of a contract, either party can apply to the court. The court may order restitution, damages, or discharge the contract. All contracts involving the transfer of real estate are considered valid until ruled otherwise.
A minor (typically under 18 or 21) can disaffirm a contract made, no matter the case. However, the entire contract must be disaffirmed. Depending on the jurisdiction, the minor may be required to return any of the goods still in his possession. Also, barter transactions such as purchasing a retail item in exchange for a cash payment are generally recognized through a legal fiction not to be contracts due to the absence of promises of future action. A minor may not disavow such a trade.Barnett, Randy E. A Consent Theory of Contracts Columbia Law Review (March, 1986) pp. 299, fn 123 Disaffirmance – it must be timely. For example, a contract that goes beyond two years of reaching the age of majority would be considered ratified. Minors are still allowed to disaffirm, even if their age is misrepresented. They will not face tort violations. Some states do not allow disaffirmance if the consideration cannot be returned. Obligations – most states hold that a minor only must return the goods (consideration) if the goods are still in the minor's possession. Many states are requiring that the minor restore the adult (other party) to the state they were in before the contract was made. Minors are beginning to be held responsible for damages, wear, tear, etc. of the good in question upon return. A suit for tort is considered by some states to be an enforcement of the contract and is not allowed. Liability – for necessities, (1) the item contracted for must be necessary for minor's existence, (2) the value must be up to that of the current standard of living or financial/social status (not excessive in value), (3) the minor must not be under the care of a parent/guardian who is required to supply the item. A minor could be held liable for a contract for the purchase of luxury items (those that are not in the financial/social/standard of living range). Ratification – accepting and giving legal force to an obligation. Express ratification (for a minor) is expressly stating, orally or in writing that he/she intends to be bound by the contract. Implied ratification is when the conduct of the minor is inconsistent with that of disaffirmance or when minor fails to disaffirm an executed contract within a reasonable period. Generally, the courts base their determination on whether the minor, after reaching the age of majority, has had ample opportunity to consider the nature of the contractual obligations he or she entered into as a minor and the extent to which the adult party to the contract has performed.Jentz, Gaylord A. and Roger LeRoy Miller Business Law Today: The Essentials South-Western College/West, Ohio, 2003 pp. 213–216 As one court put it, "the purpose of the infancy doctrine is to protect 'minors from foolishly squandering their wealth through improvident contracts with crafty adults who would take advantage of them in the marketplace.Hauer v. Union State Bank of Wautoma, 192 Wis. 2d 576, 593 (1995), quoting Halbman v. Lemke, 99 Wis. 2d 241, 245 (1980)
In Singapore, while individuals under the age of 21 are regarded as minors, sections 35 and 36 of the Civil Law Act 1909 provide that certain contracts entered into by minors aged 18 and above are to be treated as though they were adults.Civil Law Act 1909 s35-36 (Singapore). Additionally, the Minors' Contracts Act 1987 as applicable in Singapore and in England and Wales provides that a contract entered into by a minor is not automatically unenforceable and that a "court may, if it is just and equitable to do so, require the [minor] defendant to transfer to the plaintiff any property acquired by the defendant under the contract, or any property representing it".
Bankruptcy
If individuals find themselves in a situation where they can no longer pay their debts, they lose their status as credit-worthy and become bankrupt. States differ on the means whereby their outstanding liabilities can be treated as discharged and on the precise extent of the limits that are placed on their capacities during this time but, after discharge, they are returned to full capacity. In the United States, some states have spendthrift laws under which an irresponsible spender may be deemed to lack capacity to enter into contracts (in Europe, these are termed prodigality laws) and both sets of laws may be denied extraterritorial effect under public policy as imposing a potentially penal status on the individuals affected.
Enemy aliens and/or terrorists During times of war or civil strife, a state will limit the ability of its citizens to offer help or assistance in any form to those who are acting against the interests of the state. Hence, all commercial and other contracts with the "enemy", including terrorists, would be considered void or suspended until a cessation of hostilities is agreed.
Medical decisional capacity