Jury nullification was something we learned about in law school and it was a given that it was constitutional but that judges were not required to inform you about it. And I believe a Section 1983 law suit against an agent of the state depriving an individual of constitutional rights under color of law would survive a 12(b)(6) motion.
The Ninth circus (circuit) finally got one right.
Theirs probably more cases, I'm just don't have access to do the research. And I'm not going to my local county court house Law Library.