The contracting parties to an agreement are the people or entities with a direct legal stake in it, and for the contract to actually bind them, each one needs legal capacity to agree and, if signing on someone else’s behalf, authority to do so. When either piece is missing, the deal can be voided, treated as void from the start, or shifted onto the signer as a personal obligation. The rules below cover who qualifies as a party, who has capacity, how authority works inside an organization and under a power of attorney, and what happens when something is off.
Who Qualifies as a Party
A party is anyone with a direct legal stake in the agreement’s performance. Under the doctrine of privity, only the people or entities that actually entered the deal can enforce it or be sued under it. If you weren’t a party, you generally have no standing, and no obligation can be imposed on you.
Parties come in two basic forms: natural persons and legal entities. A corporation, LLC, or partnership is treated as a separate legal person, distinct from its owners. When a corporation with hundreds of employees signs a contract, the corporation is one party; the shareholders are not. That separation is a core reason people form entities in the first place.
Non-parties occasionally get enforcement rights as third-party beneficiaries, but only if the contracting parties specifically intended to benefit them. A named life insurance beneficiary is the classic example: the policyholder and insurer are the parties, but both intend the payout for the beneficiary, and the beneficiary can enforce the policy. Someone who merely happens to benefit from a deal without being targeted by it is an incidental beneficiary and has no enforcement rights.
Legal Capacity to Enter a Contract
Capacity is the legal ability to understand what you are agreeing to and be held to it. Without it, a contract is either void from the start or voidable at the option of the person who lacked capacity. Three categories of people face capacity limitations.
Minors
In most states the age of majority is 18, and contracts signed by anyone younger are voidable at the minor’s choice. The minor can honor the deal or walk away; the adult on the other side is bound either way. When a minor disaffirms, the traditional rule requires them to return whatever they still have. A growing number of courts now also require the minor to account for depreciation or damage if the original deal was fair.
A minor does not have to disaffirm immediately, but the clock starts running at 18. Continuing to use the product, making payments, or otherwise treating the contract as live can count as ratification, which locks the deal in permanently. Silence alone is not always enough, but waiting too long after reaching majority will typically forfeit the right to void.
One important exception: minors remain liable for the reasonable value of necessities like food, shelter, clothing, and medical care. If minors could void contracts for essentials, suppliers would refuse to deal with them at all.
Mental Capacity
A contract is voidable if one party could not understand the nature and consequences of the transaction because of mental illness or cognitive impairment. Courts apply a two-pronged test. Under the first prong, the person must have been unable to reasonably understand what they were agreeing to. Under the second, the person must have been unable to act reasonably in relation to the transaction, and the other party must have had reason to know of the condition. Either prong, if proven, makes the contract voidable.
When the other side acted in good faith on fair terms with no notice of the impairment, courts may limit the right to void, especially if performance is underway. Full avoidance can be conditioned on returning whatever benefits were received, so that the incapacity rules do not become a tool for unjust enrichment.
Mental capacity can also fluctuate. The lucid interval doctrine recognizes that someone with a progressive condition such as dementia may have periods of clear cognition between episodes of impairment, and a contract signed in one of those windows can be enforceable if the person genuinely understood the deal at that moment. Proving a lucid interval is difficult, and courts rarely rely on it as the sole basis for upholding an agreement.
Intoxication
Severe intoxication can make a contract voidable, but the bar is high. The impaired person must have been so intoxicated that they could not understand the nature and consequences of the deal, and the other party must have had reason to know. Having a few drinks before signing does not qualify. Courts have described the required level as intoxication that “dethroned reason.” Even when voidance is available, the person must act promptly to disaffirm once sober and still owes the reasonable value of any necessities received.
Guardianship
When a court places someone under a guardianship, the guardian typically takes over the right to manage property and enter contracts for the ward. Contracts the ward tries to sign independently after the guardianship is established are generally treated as void, not merely voidable, regardless of whether the ward happened to be lucid at the moment of signing. This is stricter than ordinary mental incapacity. A guardianship order can strip a broad range of rights, including buying or selling property, managing finances, and filing lawsuits.1U.S. Department of Justice. Guardianship: Key Concepts and Resources
Authority to Sign for an Organization
When a business entity enters a contract, a human being has to sign it. The question is whether that person had authority to commit the organization. If they did not, the contract may not bind the entity, and the signer can be left personally exposed.
Actual Authority
Actual authority exists when the organization explicitly grants someone the power to act on its behalf, typically through corporate bylaws, board resolutions, partnership agreements, or operating agreements. A CEO usually has broad express authority to sign major deals. A mid-level manager probably does not. The scope depends on what the governing documents say, and outsiders rarely see those documents unless they ask.
Apparent Authority
Apparent authority fills the gap between what an organization actually authorized and what it appeared to authorize from the outside. If a company gives someone a title, an office, business cards, and a corporate email, then puts them in front of a business partner to negotiate, the company has created the impression that this person can bind it. A third party who reasonably relies on that impression can hold the company to the contract even if the employee internally exceeded their limits. The belief has to be traceable to the organization’s own conduct, not just to what the agent claimed about themselves.
Ratification
When someone signs without proper authority, the deal is not necessarily dead. The principal can ratify after the fact, which makes the contract binding retroactively as if the authority had existed all along. Ratification can be express, through a board vote or written confirmation, or implicit, when the organization accepts the benefits of the deal with knowledge that the signing was unauthorized. Ratification must cover the entire transaction; a principal cannot cherry-pick favorable terms and reject the rest.
Verifying Authority Before Signing
Relying on someone’s business card is not due diligence. Before entering a significant contract with a business entity, confirm that the signer actually has authority. Common steps include requesting a board resolution authorizing the specific transaction, obtaining a certificate of incumbency confirming the person’s current role, and checking the entity’s good standing with the state. A certificate of good standing (sometimes called a certificate of status or existence) is issued by the state’s business filing office and confirms the entity is properly registered and current on required filings. Fees for these certificates typically range from $10 to $50 depending on the state.
Power of Attorney for Individuals
Individuals can delegate contracting authority through a power of attorney. The principal gives a written document authorizing an agent (also called an attorney-in-fact) to act on their behalf. The scope can be broad, covering virtually any transaction the principal could handle personally, or narrow, limited to a single specific deal.
The critical distinction is between durable and non-durable powers of attorney. A standard power of attorney terminates if the principal becomes mentally incapacitated. A durable power of attorney, which must explicitly state its durability, survives incapacity and remains effective until death or revocation. That makes durable powers essential for planning, since the whole point of delegating authority is often to cover situations where the principal cannot act.
An agent under a power of attorney is a fiduciary and must act solely in the principal’s best interests. When entering contracts, the agent must disclose the agency relationship to the other party. Signing without that disclosure can make the agent personally liable. The agent’s authority ends at the principal’s death, though acts performed before the agent learns of the death are typically still valid. State laws vary significantly on what agents can and cannot do, so consulting an attorney in the relevant jurisdiction is standard practice for anything beyond routine transactions.
Naming the Parties in the Document
Getting party identification wrong in a written contract seems minor until it becomes the central issue in litigation. The preamble should include each party’s full legal name as registered with the state, not a marketing name, nickname, or DBA. Adding the entity type (corporation, LLC, limited partnership), the state of formation, and a primary business address removes ambiguity when similar names exist.
Contracts then assign shorthand labels such as “Buyer,” “Seller,” “Licensor,” or “Landlord” after the initial identification. These defined terms stay capitalized throughout the document to signal they refer to the specific entities named in the preamble.
Businesses sometimes operate under a name different from their registered legal name. A “doing business as” (DBA) or assumed name is legal, and contracts entered under it are generally valid. The risk is failing to connect the DBA to the actual legal entity. If someone signs using only a trade name or division name without disclosing the underlying corporation or LLC, courts in many jurisdictions treat that as a failure to identify the principal, and the signer can end up personally liable for what they assumed were company obligations. Most states require assumed names to be registered, and some bar unregistered businesses from enforcing contracts until they comply.
The signature block matters as much as the preamble. When someone signs for a business entity, the block should include the entity’s legal name, the word “by” or “on behalf of” before the signature, and the signer’s title afterward. Listing a title under a name without these agency indicators can be read as merely identifying the person rather than limiting the capacity in which they signed, and courts have held signers personally liable based on exactly that ambiguity. The safest approach uses three elements: the principal’s name is disclosed, words of agency precede the signature, and the signer’s representative title follows it.
When Capacity or Authority Is Missing
A contract tainted by a capacity or authority problem does not just quietly disappear. The consequences depend on the type of defect and who knew what.
Voidable contracts, such as those signed by minors or people with mental impairments, remain enforceable unless and until the affected party acts to disaffirm. The other side cannot void the contract on its own. When disaffirmance happens, both sides generally have to return what they received. Under the traditional rule for minors, the minor only has to return whatever is left, even if the goods are damaged or depreciated, though a growing number of courts now require compensation for wear and tear when the original deal was fair.
Void contracts, such as those entered by a person under a court-appointed guardianship, have no legal effect from the beginning, and neither party can enforce them. Even here, though, the person who lacked capacity still owes the reasonable value of any necessities received. That prevents someone from receiving medical care, shelter, or food under a contract and then claiming it was void to avoid paying anything.
Authority defects create a different problem. If someone signs without authorization and the principal does not ratify, the entity is not bound. The signer, however, can be personally liable to the other party for damages caused by misrepresenting their authority. When the misrepresentation was intentional, the signer faces potential fraud claims, with damages designed to put the injured party in the position they would have occupied if the representation had been true. Even an honest mistake about authority can leave the signer holding the bag, which is why organizations should put authority in writing before anyone picks up a pen.