What is Estoppel?
Estoppel is a notoriously vague and hard-to-pin-down term in legal terminology. Derived from the French, estoppel literally means "stopped," as in a person is stopped from doing or saying something. This rather broad definition has given rise to many different forms of estoppel, such as estoppel by deed, issue estoppel, estoppel by negligence, estoppel by election, and so on. The difficulty of describing estoppel was noted by Lord Denning, when he said that estoppel consists of "several rooms [that] have this much in common: they are all under the same roof. Someone is stopped from saying something or other, or doing something or other, or contesting something or other. But each room is used differently from the others." With such difficulty in mind, below is a look at just three of, arguably, the most important types of estoppel.
Equitable estoppel occurs when a party to a legal claim or defense is stopped from taking legal action that is inconsistent with that party's previous words, claims, or conduct. Essentially, equitable estoppel prevents a party from going back on his or her word. For example, if neighbor A accidentally builds on neighbor B's property and neighbor B, knowing it is his property nonetheless tells neighbor A that he can continue to build, neighbor B cannot later bring legal action against neighbor A over the structure on his property. In legal terms, neighbor B would be estopped by the courts since his claim would run counter to his earlier permission giving neighbor A the right to build.
Promissory estoppel, meanwhile, concerns contract law. One party cannot promise the other party to the contract that part or whole of the contract will not be enforced and then later try to enforce the part or whole of the contract in question. For example, if an employer tells a potential employee that a non-compete clause will not be enforced, that employer cannot later attempt to enforce that employee to abide by that same non-compete clause.
Finally, collateral estoppel prevents a person from bring forth litigation multiple times once a court has already ruled on the matter. Essentially, collateral estoppel prevents a party from bringing a grievance to a court after another court has already ruled on the issue at hand. Collateral estoppel is designed to prevent judicial harassment, such as one party bringing a lawsuit against another party in one country, failing in his or her claim, and then trying to bring that lawsuit against the same party but through a different country's court. It is important to not, however, that collateral estoppel does not prevent appeals.
Estoppel is a vast and important area in common law legal systems. Although often unwieldy and hard to define, estoppel has the ability to help prevent wasting of court resources and to ensure that parties to a claim or defense are protected from judicial abuse. However, while estoppel provides important protections, it also prevents (or stops) people from exercising what in other circumstances may be considered their legal rights. As a result, estoppel is a controversial area of law that is constantly evolving.