What is the legal doctrine that prevents someone from exercising a right or privilege?

The legal doctrine that prevents someone from exercising a right or privilege is known as estoppel. This principle applies in situations where a party has made a representation or has taken a position that another party has relied upon, leading to a situation where it would be unfair to allow that party to change their position to the detriment of the relying party. Estoppel effectively bars a party from asserting a claim or right that contradicts what has previously been established as true, especially if this alters the situation to the disadvantage of another who relied on the original representation.

For instance, in insurance contexts, if an insurer has acted in a way that suggests coverage will be provided and the insured has relied on that representation, estoppel may prevent the insurer from later denying coverage based on a technicality. Thus, estoppel serves to uphold fairness in transactions and relationships, ensuring that parties cannot act in a way that would harm others after they have led them to act based on certain representations.

The other terms relate to different legal concepts: Res Judicata refers to the principle that a matter already judged cannot be re-litigated, a quasi-contract involves an obligation created by law to prevent unjust enrichment without a formal agreement, and jurisdiction pertains to the authority of a court to