Halachically, what are the responsibilities of one who is called to jury duty? What if one of the litigants is Jewish, and the halacha would find differently than civil law does in the case, are you considered to have financially damaged him?
R. Moshe (in Hoshen Mishpat 1:92) considers the case where one wants to work as a tax enforcement officer where he might have to turn over Jews to the government to be punished "more than they would be according to the rules of Torah". R. Moshe answer he can take the job, but his first proof is from a case in the gemara where the Jew is forced to inform on another Jew. He then extends that to include also the case of the tax officer who voluntarily applies for the job, and allows it even then. I would liken the juror to the first case and say that based on his logic, jury service is certainly allowed even if the verdict is not according to the Torah law.