Legal Definitions - estop

To estop means to legally prevent a person or party from asserting a particular claim, right, or argument in a court of law. It is a fundamental principle used by judges to ensure fairness and consistency, often when a party's previous actions, statements, or a prior legal decision contradict a new position they are trying to take. The broader legal doctrine that allows this prevention is known as "estoppel."

Here are some examples illustrating how a court might estop a party:

• Example 1: Contractual Promises

  A small business owner, Sarah, verbally promises her long-time supplier, Mark, that she will purchase a large order of custom materials for an upcoming project. Relying on this promise, Mark invests significantly in raw materials and specialized equipment to fulfill the order. If Sarah then tries to back out, claiming no formal written contract was ever signed, a court might estop her from making that argument.

  Explanation: The court would prevent Sarah from denying a contract exists because Mark reasonably relied on her promise to his detriment (investing money and resources), making it unfair for her to suddenly change her position.

• Example 2: Prior Legal Decisions

  In a personal injury lawsuit, a jury specifically determined that a particular traffic light was functioning correctly at the time of an accident. Later, in a separate but related lawsuit involving the same accident, one of the parties attempts to argue that the traffic light was actually broken.

  Explanation: The court would estop that party from re-arguing the issue of the traffic light's functionality. Since that specific issue was already fully and fairly decided in the first trial, it cannot be brought up again in a subsequent legal proceeding.

• Example 3: Consistent Conduct

  A homeowner, Mr. Henderson, consistently allows his neighbor, Ms. Davies, to use a portion of his driveway to access her garage for over ten years, never objecting and even helping her clear snow from it. When a dispute arises between them, Mr. Henderson suddenly tries to block Ms. Davies from using that part of the driveway, claiming it's his private property.

  Explanation: A court might estop Mr. Henderson from preventing Ms. Davies' access. His long-standing conduct and implied permission led Ms. Davies to reasonably believe she had a right to use that portion of the driveway, and it would be unfair to allow him to revoke that access abruptly after such a long period.