The article deals with the problem of the mechanism of using such a method of protecting rights as nonuse of an act contrary to law in litigation. The paper demonstrates the duality of the considered method of protection: as a way of protecting subjective civil rights and as the embodiment of the principle of legality. The procedural mechanism of its implementation (by an application of the party to the dispute or ex officio by the court; in the form of an objection to the claim or in the form of a counterclaim) depends on the essence of the method of protection of the right. By the example of the decision of the Arbitration Court of the Moscow Region the author considers the problem of the admissibility of the non-use by the court of an unlawful individual act by the statement of the authority that issued the act and the possibility of a negative result of the non-use of the illegal act for a private person. Special attention is paid to the question of the legality of the objection about the illegal act by t