What is the threshold matter for a defendant to rely on a qualified immunity defense?

As a threshold matter, Appellants are correct that the magistrate judge was mistaken when he stated that "[f]or defendants to rely on a qualified immunity defense, defendants would first have to admit that they in fact violated this clearly established constitutional right." Quite the contrary, defendants need not admit that plaintiff's factual allegations are true in order to assert this defense. The very heart of qualified immunity is that it spares the defendant from having to go forward with an inquiry into the merits of the case. Instead, the threshold inquiry is whether, assuming that what the plaintiff asserts the facts to be is true, any allegedly violated right was clearly established. The right itself is the matter of discussion, not whether that right was in fact violated. See Harlow v. Fitzgerald, 457 U.S. 800, 818, 102 S.Ct. 2727, 2738, 73 L.Ed.2d 396 (1982); see also Siegert v. Gilley, 500 U.S. 226, 232, 111 S.Ct. 1789, 1793, 114 L.Ed.2d 277 (1991).