What does the doctrine of estoppel prevent a party from doing?

The doctrine of estoppel plays a crucial role in preventing a party from arguing something contrary to a previous claim or act. This principle is grounded in fairness and consistency, ensuring that parties cannot take positions that contradict their prior statements, actions, or representations when another party has relied on those statements or actions to their detriment.

For example, if a party has led another party to believe that a certain condition exists—such as the existence of a contract or the performance of an obligation—then that first party cannot later assert a different position that would unjustly disadvantage the second party who relied on the original claim. This reliance can create a binding effect that effectively "estops" the party from changing their stance.

In the context of the other options, changing the terms of a contract or enforcing an expired contract does not directly relate to the doctrine of estoppel. Similarly, withdrawing from a contract without cause does not inherently involve reliance or misleading actions that estoppel seeks to remedy. Thus, the core focus of estoppel is on preventing contradictions after a party has established a particular understanding or expectation through their prior conduct.