What is the legal test for a qualified-immunity defense?

If the facts as alleged would not amount to the violation of a constitutional right, the qualified-immunity inquiry is at an end, and summary judgment must be granted. Id. "On the other hand, if a violation could be made out on a favorable view of the parties' submissions, the next, sequential step is to ask whether the right was clearly established." Id. According to this second inquiry, a qualified-immunity defense will be successful either when the defendants' actions did not violate clearly established law or when it was objectively reasonable for the defendants to believe that their actions did not violate such law. Poe v. Leonard, 282 F.3d 123, 133 (2d Cir.2002).