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Kevin O'Flaherty

A contract is unenforceable when there is evidence of lack of capacity, coercion, undue influence, misrepresentation/nondisclosure, unconscionability, violation of public policy, or impossibility. What makes an Illinois contract unenforceable emerges in legal disputes where the validity of an agreement is contested. This article will unpack the various legal defenses and why a contract may be null and void. By the end of this article, you should better understand some of the basic, key principles of Illinois contract law, the most common reasons a contract is not legally binding, and what to do if you find yourself on either end of an unenforceable contract.

Illinois Contract Law: Key Principles

Contracts play a crucial role in all business dealings and knowing the specific regulations in Illinois is essential. These guidelines outline the terms and conditions of contracts as well as specify the responsibilities of each party involved. The state’s statutes, known as the Illinois Compiled Statutes, contain clear definitions and requirements that must be followed when using state or federal funds.

To set terms and conditions, these laws also require proper documentation for contracts involving public funds. This ensures compliance with both state and federal standards while promoting transparency and accountability. Financial transactions are governed by Illinois law, which outlines how awards from government entities should be treated by recipients along with their obligations. Failure to adhere to these provisions can result in enforcement through defined consequences stated within the Illinois Compiled Statutes.

What Does it Mean for a Contract to be Unenforceable?

An unenforceable contract is a contract that is valid but one that a court chooses not to enforce. Unenforceable is usually used in contradistinction to either void the contract or make it voidable. A void contract is a contract that is not legally valid. A voidable contract occurs when one party is not legally bound to the agreement. A contract may become the subject of a court case when a dispute arises among parties or when the enforceability of parts of the contract or the contract as a whole comes into question. An excellent example of a contract being unenforceable and becoming voidable is if a minor becomes a party to a contract; more on this example can be found in our article on “How Old Do You Need to be to Form a Contract?”

For a contract to be legally valid, it must include an offer to enter into an agreement, an acceptance of that offer, and consideration (see our article on consideration). In order to be enforceable in a court of law, the contract must both be legally valid, and the party against whom enforcement of the contract is sought must not have any valid defenses to breach of contract claims. 

A court may find a contract to be unenforceable because of the contract’s subject matter, because one party took advantage of the other party in the agreement, or because there is a lack of sufficient proof of the agreement. Additionally, there are eight specific criteria a court will use to determine whether or not a contract is unenforceable: lack of capacity, coercion, undue influence, misrepresentation and nondisclosure, unconscionability, and public policy, mistake, and impossibility.

Lack of Capacity to Contract Explained

Lack of capacity to contract occurs when at least one party does not have the ability to understand what it is he or she agrees to. If it appears that one party does not have this reasoning capacity to fully understand the terms of the agreement, the contract may be found unenforceable against that person.

Common examples of a contract being unenforceable due to lack of capacity are when one side is too young or when one party has a mental disability that prevents him or her from understanding the agreement and its implications. The purpose of finding a contractor to be unenforceable due to lack of capacity is to prevent one party from taking advantage of someone who does not have the reasoning ability to make a decision to form a contract.

Coercion as a Contract Defense

A contract signed under coercion, or duress, will be unenforceable. To prove coercion, there must be evidence that indicates someone was threatened into agreeing to the terms of the contract. A typical example of coercion is blackmail. For a court to deem a contract unenforceable due to coercion, sufficient evidence must be gathered for proof that a party agreed to a contract while under financial or physical duress.

Undue Influence as a Contract Defense

Undue influence refers to a party that persuades another party to enter into an agreement by taking advantage of the parties’ relationship and using pressure tactics to encourage the other into forming a contract. To prove undue influence, one party must prove the other used excessive pressure during the process and that, for whatever reason, he or she was susceptible to that pressure. To prove undue influence, the party could also provide evidence that the other exploited a confidential relationship to influence the formation of the contract. Similar to lack of capacity and coercion, a contract may be unenforceable because of undue influence to protect one party from being taken advantage of by another party.

Misrepresentation and Nondisclosure as a Defense to Breach of Contract

Misrepresentation generally refers to a false statement from one party or concealment of information on a matter concerning the contract. If it’s found that any fraud or misrepresentation occurred during the negotiation process, the resulting contract will most likely be held unenforceable.

Nondisclosure is essentially misrepresentation through silence, meaning one party neglected to disclose a pertinent fact regarding the agreement. In the case of nondisclosure, courts will consider whether a party had a duty to disclose the information or if the other party could’ve easily accessed the same information another way. Material facts are generally those that each party has a duty to disclose.

Unconscionability as a Defense to Breach of Contract

Unconscionability refers to a term in the contract, or possibly the contract in its entirety, that is so decisively unfair that the contract cannot exist the way it presently stands. When scrutinizing the case, the court will look at whether one side has grossly unequal bargaining power, if one side had difficulty understanding the terms (due to language or literacy issues, for example), or whether the terms themselves were simply manifestly unfair.

If the court does find a contract to be unconscionable, it has other options rather than voiding the contract altogether. For example, the court may elect to enforce the conscionable parts of the contract and have the unconscionable terms rewritten.

When Does Public Policy Make a Contract Unenforceable?

Contracts that are found to be unenforceable based on public policy are intended not only to protect the parties involved but also to prevent the contract and contracts like it from posing harm to society as a whole. Additionally, a court will never enforce a contract that includes something in its terms that’s already against state or federal law.

Some examples of contracts being held unenforceable because of public policy include an employer forcing an employee to sign a contract forbidding medical leave, an employer making an employee sign a contract that keeps them from joining a union, or a landlord forcing a tenant to sign a contract forbidding medically necessary companion animals from living at the residence.

Mistake as a Defense to Breach of Contract

The unenforceability of a contract doesn’t always have to deal with ill-intent or bad faith. Sometimes an honest mistake could be made in the contract that renders it unenforceable. If one party is responsible for the mistake, it’s called a unilateral mistake. If both parties are at fault, it’s referred to as a mutual mistake. The mistake in question must have been related to something important in the agreement and have a significant effect on the exchange per the agreement. In either case, the terms of the agreement that contain the mistake must be rewritten in order for the contract to be enforceable.

Impossibility as a Defense to Breach of Contract

In some instances, a contract will be deemed unenforceable because it would be impossible or impracticable to carry out its terms. Something is too difficult or too expensive could be grounds for impossibility. Another good example could be the transaction of a crop that was wiped out during a natural disaster. If there was a contract that the crop is to be sent somewhere, the contract would be unenforceable as it would be impossible for the one party to send something that no longer exists.

To prove impossibility, the one party will need to gather evidence to show it cannot complete its duty due to an unexpected event that it has no control over, or the party must prove that performing its duty to the contract is much more difficult or expensive now because of an outdoor event.


Mastering the intricate realm of Illinois contract law can be challenging, but with proper understanding, it becomes significantly easier. From comprehending the essential components that make a valid contract to identifying potential factors that may render contracts unenforceable, possessing this knowledge is crucial in avoiding legal obstacles. It’s important to always keep in mind that seeking legal guidance when uncertain is highly recommended.

Contracts are not merely written documents. They serve as pillars for business deals and have significant impact on relationships and decision-making processes. With a solid grasp of key aspects concerning Illinois contract law, one can confidently maneuver through its complexity and ensure the durability of agreements made. Remember: information holds power (especially within contractual matters), making it an invaluable tool at your disposal.

Frequently Asked Questions

What are 3 defenses that can be used against the enforcement of a valid contract?

Three frequently used defenses against the enforcement of a legitimate contract are lack of capacity, undue influence, and unconscionability. These defense mechanisms can be utilized to question the legality of an agreement or mitigate liability for any resulting damages.

When can a contract be unenforceable?

If the subject matter of a contract is illegal or if one party takes advantage of the other, it may be considered unenforceable. If there is insufficient evidence to support the agreement between parties, it can also render the contract invalid.

Ultimately, all involved individuals must comply with legal and ethical principles during contractual proceedings in order for agreements to hold weight. This ensures fair treatment and proper conduct among both parties throughout the entire process.

What is an example of an unenforceable contract?

An instance of a contract that cannot be enforced is one in which an illegal act is involved, for example, a sale agreement for illicit drugs. It cannot be enforced without violating the law.

What makes a contract legally valid in Illinois?

In the state of Illinois, a contract is considered legally binding when it includes an offer, acceptance, and consideration. These factors are crucial in guaranteeing that the terms of the agreement can be enforced.

What does unconscionability mean in the context of Illinois contract law?

In Illinois contract law, the concept of unconscionability pertains to conditions or clauses within a contract that are deemed excessively unjust and cannot be upheld in their current form.

Disclaimer: The information provided on this blog is intended for general informational purposes only and should not be construed as legal advice on any subject matter. This information is not intended to create, and receipt or viewing does not constitute an attorney-client relationship. Each individual's legal needs are unique, and these materials may not be applicable to your legal situation. Always seek the advice of a competent attorney with any questions you may have regarding a legal issue. Do not disregard professional legal advice or delay in seeking it because of something you have read on this blog.


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