What is the test for qualified immunity for civil damages in a civil case brought by a former employee of the Department of Justice who is accused of misusing his position as a witness?

Defendants argue that they are entitled to qualified immunity. Government officials enjoy qualified immunity from civil damages unless their conduct violates "clearly established statutory or constitutional rights of which a reasonable person would have known." Harlow v. Fitzgerald, 457 U.S. 800, 818, 102 S.Ct. 2727, 2738 (1982). "Qualified immunity balances two important interests-the need to hold public officials accountable when they exercise power irresponsibly and the need to shield officials from harassment, distraction, and liability when they perform their duties reasonably, " Pearson v. Callahan, 129 S.Ct. 808, 815 (2009), and protects "all but the plainly incompetent or those who knowingly violate the law, " Malley v. Briggs, 475 U.S. 335, 341, 106 S.Ct. 1092, 1096 (1986).