Prevention doctrine is a common-law principle of contract law which says that a contracting party has an implied duty not to do anything that prevents the other party from performing its obligation. A party who prevents performance of a contract may not complain of such nonperformance.
The following are examples of case law defining prevention doctrine:
If a party to a contract is himself the cause of the failure of performance, either of an obligation due from him or of a condition upon which his liability depends, he cannot take advantage of the failure.[Meson v. GATX Tech. Servs. Corp., 507 F.3d 803, 806 (4th Cir. Md. 2007)]
The prevention doctrine is a generally recognized principle of contract law according to which if a promisor prevents or hinders fulfillment of a condition to his performance, the condition may be waived or excused. [Barnhill v. Veneman (In re Peanut Crop Ins. Litig.), 524 F.3d 458 (4th Cir. N.C. 2008)]
The prevention doctrine entails that, where one party to a contract takes an action that prevents the other party from being able to fulfill a condition precedent to that contract, the first party may not use its own action as a mechanism for avoiding performance of its contractual obligations. [General Datacomm Indus. v. Arcara (In re General Datacomm Indus.), 407 F.3d 616, 626 (3d Cir. Del. 2005)]
Prevention doctrine is also known as prevention of performance doctrine.