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Why Ab Initio Is a Big Deal in Contract Law

Why Ab Initio Is a Big Deal in Contract Law


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The phrase ab initio comes from Latin and literally means “from the start” or “from the beginning.” Such a definition may sound fairly innocuous, but the truth is that this little phrase has a big impact on legal decisions. From striking down bad contracts to protecting people from excessive police powers, the declaration that something is the case ab initio can have major reverberations for lawyers, businesses, and private individuals. Here’s a look at what ab initio is and when and why it matters.

From the start

As stated above, ab initio means “from the start.” Therefore, if a court declares something to be the case ab initio, it typically means that the court’s ruling on it applies from when an act occurred or when the circumstances for the case in question were in effect, rather than from the point in time when the court actually ruled on the matter. To put it in simpler terms, if a court declares a contract to be void ab initio, it means that that contract is considered invalid from the time it was written and/or signed (i.e., from the start of the contract) rather than from when the court declared it to be null or void. 

Ab Initio and Contract Law

Ab initio in contract law 

Ab initio is an especially important concept to know for contract law. If a court declares a contract void ab initio, then the contract cannot be remedied or modified to correct whatever was wrong with the contract in the first place. Essentially, if a contract is declared void ab initio, the ruling effectively means that the contract essentially never existed and therefore had no binding power over any parties to the contract. For example, if a person signs a contract either under duress or while being misled about the contents of the contract:

    1. Then a court will likely declare that contract to be void ab initio since the person either was not able to sign the contract under his or her own free will.
    2. He or she did not have enough information to know what he or she was agreeing to.

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Trespassing ab initio 

The concept of ab initio doesn’t just apply to contracts, however. In rare cases, it can also be used as a check on the power of public officers. Although rare nowadays, something being declared ab initio can protect private citizens from abuse of state power. For example, a police officer may have a court order to enter a person’s private property and seize a piece of jewelry that is considered stolen goods. If, however, that police officer enters the house and takes that person’s television set, the courts will consider the officer to have exceeded his or her authority and to have used the court order as a pretense for committing an unlawful act. Therefore, although the court order itself was legal, the officer will have been considered to be trespassing ab initio. Again, however, the use of ab initio to reign in abuse by police is rarely used nowadays.


This article contains general legal information but does not constitute professional legal advice for your particular situation. The Law Dictionary is not a law firm, and this page does not create an attorney-client or legal adviser relationship. If you have specific questions, please consult a qualified attorney licensed in your jurisdiction.

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