There's no subtlety. If it was later found out he was actually guilty but the jurors cut him loose, he cant be tried again and the jurors can't get in trouble for not finding him guilty when he was (and they would have found him guilty had they known). They couldn't have known, it's just common sense to not prosecute them.

There's also no armchair quarterback, thats not what that means. In none of my comments am i specifying what I would have done in either persons position from my armchair. I'm just stating facts about the law. (Not giving advice either).

Theres subtlety in jury nullification, but not in the jurors immunity. It comes from multiple laws and has precedence.

1. Tanner v. United States, 483 U.S. 107 (1987) – The Supreme Court reaffirmed that juror deliberations are generally protected from inquiry, ensuring that jurors cannot be punished for their reasoning or decisions.

2. United States v. Dougherty, 473 F.2d 1113 (D.C. Cir. 1972) – This case discusses jury nullification, reinforcing that jurors have the right to acquit regardless of the evidence and cannot be penalized for doing so.

3. Rule 606(b) of the Federal Rules of Evidence – This rule limits the ability to challenge a verdict based on jurors' thought processes during deliberation, further shielding them from liability.