"It was, however, clearly established that filing a lawsuit was constitutionally protected conduct. See Milhouse v. Carlson, 652 F.2 d 371, 37 3-74 (3d C ir. 1981); see also California Motor Transport Co. v. Trucking Unlimited, 404 U.S. 508, 510 (1972) (access to courts is one aspect of the First Amendment right to petition the government for grievances). Moreover, it was also clearly established that the government cannot retaliate against someone for engaging in constitutionally protected activity in a way that would chill a reasonable person in the exercise of the constitutional right. See Rutan v. Republican Party of Illinois.", 497 U.S. 62, 73 , 76 n.8 (1990).  UNITED STATES SUPREME COURT  (emphasis added)