This from Patterico the other day:
Yesterday I asked people who support jury nullification what they would do if they perceived a conflict between the rule of law and the dictates of their own conscience. I asked: if the evidence showed beyond a reasonable doubt that the defendant was guilty of a breaking a valid law, but convicting the defendant appeared to be an unjust result, would you:
a) follow the law and convict;
b) follow your conscience and acquit; or
c) ask to get off the jury?
His comments here.