Legitimate excuses for nonperformance of contractual duties fall into a few recognized categories: the other party breached first, an event after signing made performance impossible or pointless, a clause in the contract covers the situation, a condition the duty depended on never happened, or the agreement was defective from the start. Each excuse has its own requirements, and courts apply them strictly. Which one fits your situation determines whether you owe damages, get your money back, or walk away clean.
The Other Side Breached First
The most common real-world excuse is that the other party failed to perform first. Contract law treats each side’s performance as tied to the other’s. When one side commits a material failure, the other side’s duty is suspended, and if the breach goes uncured, eventually discharged. You shouldn’t have to keep paying a contractor who stopped showing up.
Not every breach qualifies. The failure has to be material, meaning it goes to the heart of what was bargained for. A contractor who finishes a building one day late probably hasn’t committed a material breach. A contractor who installs the wrong foundation has. Courts weigh how much of the expected benefit the non-breaching party actually received, whether the breach can be fixed, and how much harm it caused.
You can also be excused when the other side announces in advance that it won’t perform. Under the UCC, when either party repudiates a performance not yet due and that repudiation would substantially impair the contract’s value, the other side can suspend its own performance immediately and pursue remedies for breach.1Legal Information Institute. Uniform Commercial Code 2-610 – Anticipatory Repudiation You don’t have to wait and hope. The same principle applies outside the UCC in common law contracts, though the terminology varies by jurisdiction.
Performance Became Impossible or Impracticable
Sometimes an event occurs after the contract is signed that makes performance genuinely impossible. The classic example is a personal services contract where the person hired dies or becomes incapacitated. If you hire a specific artist to paint your portrait and the artist suffers a stroke, the duty to paint is discharged. The same applies when the subject matter of the contract is destroyed: a contract to sell a specific building is excused if the building burns down before closing.
Three things must be true for impossibility to work. The event must occur after the contract was formed, not before. It must not be the fault of the party claiming the excuse. And its non-occurrence must have been a basic assumption both parties shared when they made the deal. A seller who burns down their own warehouse doesn’t get to claim impossibility.
Commercial Impracticability
Performance doesn’t have to be literally impossible to be excused. When an unforeseen event makes performance unreasonably difficult or expensive in a way that fundamentally changes the nature of the obligation, courts may excuse it as impracticable. The bar is high. A price increase alone, even a steep one, almost never qualifies. What qualifies is something like a war or natural disaster shutting down the only viable supply chain, or a trade embargo eliminating the sole source of a required material.
For sales of goods, UCC Section 2-615 codifies this principle. A seller’s failure to deliver is not a breach if performance was made impracticable by an unforeseen contingency that both parties assumed wouldn’t happen when they signed. The same section covers compliance with government regulations or orders, whether domestic or foreign, even if the regulation later turns out to be invalid.2Legal Information Institute. Uniform Commercial Code 2-615 – Excuse by Failure of Presupposed Conditions That last point matters: if a new law prohibits what the contract requires, you don’t have to bet on whether the law will be overturned.
A seller claiming impracticability under the UCC can’t just go silent. Section 2-615 requires prompt notice to the buyer that there will be a delay or non-delivery. If the disruption only partially affects capacity, the seller has to allocate remaining production fairly among customers and tell each buyer what share they can expect.2Legal Information Institute. Uniform Commercial Code 2-615 – Excuse by Failure of Presupposed Conditions Skipping that notice can undermine the entire defense.
Supervening Illegality
A specific form of impracticability arises when a new law or government order makes performance illegal after the contract was signed. If the government bans the export of certain goods, a seller who contracted to ship those goods abroad is excused. The law can’t simultaneously require you to perform and prohibit you from doing so. Courts treat the government regulation itself as the kind of unforeseen event that satisfies the impracticability standard.
The Purpose of the Deal Collapsed
Frustration of purpose is different from impossibility in a way that trips people up. With impossibility, you can’t do what you promised. With frustration, you can still do it, but the entire reason for the contract has evaporated. You rented a storefront for a pop-up shop during a festival, and the festival is canceled. You can still occupy the storefront. The thing that made the lease worth signing no longer exists.
Courts are careful with this doctrine because almost any contract could be reframed as having a frustrated “purpose.” To succeed, you have to show that the frustrated purpose was the principal reason for the contract, that both parties understood this, and that the frustrating event was not your fault and was not something you should have anticipated. A general economic downturn that makes a business lease less profitable does not frustrate the lease’s purpose. The purpose of the lease was to occupy commercial space, and that purpose still exists.
A Force Majeure Clause Covers the Event
The doctrines above apply even when the contract doesn’t mention them. Force majeure clauses are different: they are terms the parties write into the contract to define specific events that excuse performance. Common triggers include natural disasters, pandemics, wars, terrorism, government actions, and labor strikes, though the exact list varies.
Courts interpret these clauses narrowly. If the clause lists “earthquakes, floods, and hurricanes” but doesn’t mention pandemics, a court is unlikely to stretch it to cover a disease outbreak. The closer your situation matches the language in the clause, the stronger the defense. Vague catch-all phrases like “and other events beyond the parties’ control” offer less protection than people assume.
Most force majeure clauses also require the affected party to notify the other side within a specified window, often five to ten days after the triggering event. Some require written proof that the event occurred and documentation of its expected duration. Failing to follow these procedures can kill the defense entirely, even when the underlying event clearly qualifies. If your contract has a force majeure clause, read the notice requirements before doing anything else.
When a contract lacks a force majeure clause, the party seeking an excuse falls back on the common law doctrines of impossibility, impracticability, and frustration of purpose. Those doctrines set a higher bar than most contractual force majeure provisions, which is exactly why parties negotiate force majeure clauses in the first place.
The Contract Was Defective From the Start
The excuses above all assume the contract was valid when it was made and something went wrong afterward. A separate category involves contracts that were flawed from day one. If the agreement itself was defective, a court can declare it void or voidable, releasing one or both parties.
Mutual Mistake
When both parties share a mistaken belief about a material fact at the time they sign, the adversely affected party can void the contract. The mistake has to concern a basic assumption of the deal and must have a material effect on what was exchanged. Two people contract for the sale of a parcel of land, both believing it contains mineral deposits. The land turns out to be geologically worthless. The buyer can likely void the agreement because the shared assumption that made it worthwhile was wrong.
A unilateral mistake, where only one party is wrong, is much harder to use as an excuse. It typically works only if the other party knew or should have known about the mistake, or if enforcing the contract would be unconscionable.
Duress and Undue Influence
A contract signed under duress is voidable by the person who was coerced. Duress requires an improper threat that leaves the victim no reasonable alternative but to agree. Improper threats include threatening a crime or tort, threatening criminal prosecution to extract a business concession, or abusing civil legal process in bad faith. A threat can also be improper when the resulting deal is unfair and the threatening party gains no legitimate benefit from carrying it out.
Undue influence is a subtler form of coercion. It arises when someone in a position of trust or authority exploits that relationship to push the other person into an unfair agreement. An elderly person’s caregiver pressuring them to sign over property, or a financial advisor steering a client into a one-sided arrangement, both fit. The power imbalance substitutes for the explicit threat required in duress cases.
Misrepresentation
If one party makes a false statement about a material fact and the other party reasonably relies on that statement in entering the contract, the deceived party can void the agreement. The false statement has to be about something concrete, not a vague opinion or sales puffery. A seller who says “this car is in great shape” is expressing an opinion. A seller who says “this car has a brand-new engine” is making a factual claim, and if the engine has 80,000 miles on it, the buyer has grounds to walk away.
Misrepresentation can be fraudulent, where the person knows the statement is false, or innocent, where the person genuinely believes it. Both can void the contract, though fraud also opens the door to additional damages.
Unconscionability
A court can refuse to enforce a contract, or strike individual clauses from it, if the terms are so unfair they shock the conscience. The defense has two components. Procedural unconscionability looks at how the deal came together: unequal bargaining power, hidden terms, high-pressure tactics. Substantive unconscionability looks at the terms themselves, such as a price wildly disproportionate to the value exchanged, or a clause stripping one party of all meaningful remedies. Courts are most likely to find unconscionability when both elements are present.
For sales of goods, UCC Section 2-302 gives courts the power to refuse enforcement of an unconscionable contract or cut the offending clause while enforcing the rest. Before ruling, the court must give both parties a chance to present evidence about the commercial context and the clause’s practical effect.3Legal Information Institute. Uniform Commercial Code 2-302 – Unconscionable Contract or Clause The same principle applies in common law contracts outside the UCC.
Lack of Capacity
Certain people lack the legal capacity to be bound. Minors, generally anyone under eighteen, can enter contracts but can also walk away from them. A minor’s contract is voidable at the minor’s option, not the adult’s. If a sixteen-year-old buys a car and later decides to return it, the minor can disaffirm and get their money back. The adult seller has no equivalent right.
There are limits. Contracts for necessities like food, shelter, and medical care are generally enforceable against minors, at least to the extent of the reasonable value of what was provided. Some states also make specific categories nonvoidable for minors, such as insurance, educational loans, or bank accounts. People who lack mental capacity to understand the nature of a transaction can also void contracts, though the standards vary by jurisdiction.
A Required Condition Never Happened
Many contracts don’t create unconditional obligations. They make one party’s duty depend on something specific happening first. These are conditions precedent, and if the condition doesn’t occur, the duty it was attached to never kicks in. Failing to perform a duty that was never triggered isn’t a breach.
The familiar example is a real estate purchase agreement that conditions the buyer’s obligation to close on obtaining mortgage financing at specified terms. If the buyer applies in good faith but gets denied, the condition has failed. The buyer doesn’t have to go through with the purchase, and the earnest money deposit is returned.
Other common conditions include a home inspection revealing no major defects, an attorney review period expiring without objection, or a contingency that the buyer’s existing home sells first. Each creates an exit that isn’t a breach, as long as the condition genuinely wasn’t met and the party relying on it acted in good faith.
Watch out for waiver. A party can lose the protection of a condition by acting as if it doesn’t matter. If the home inspection reveals a cracked foundation and the buyer continues negotiating without raising the issue, a court may find the buyer waived the inspection contingency. Waiver can be explicit or implied from conduct, and it requires intent. Courts look at what you did, not just what you said, and doubtful cases tend to be decided against the party claiming a condition was waived.
The Agreement Was Never Put in Writing
Certain contracts are unenforceable unless they are in writing and signed by the party being held to them. This rule, the statute of frauds, covers contracts for the sale of land, agreements that can’t be performed within one year, promises to pay someone else’s debt, and contracts for the sale of goods above a threshold dollar amount (typically $500 under the UCC). If a contract falls into one of these categories and there’s no written agreement, the party being sued can raise the statute of frauds as a complete defense.
The writing doesn’t need to be a formal contract. A signed letter, email, or even a text message confirming the deal’s key terms can satisfy the requirement. Between merchants under the UCC, a written confirmation sent by one party and not objected to within ten days can bind both sides. Courts have also carved out exceptions where one party has substantially performed, or where the party seeking enforcement admits in court that a deal was made. The safest approach for any contract in these categories is to get the essential terms in writing before performance begins.