Does this apply even to sitting on a jury for a trial where all the parties are not Jewish?

Shalom uvracha, According to halacha, a Jew must go only to a Jewish court, and anyone who goes to a non-Jewish court is 'raising his hand' against the Torah. Instead of going to the bait din to hear Dvar Hashem, the Torah ruling, he goes to the non Jewish courts, and he is condemned for this. (see Shulchan Aruch Choshen Mishpat, 26:1). There is a disagreement among poskim about the permissibility of participating in a jury. Rav Menashe Klein in his book Mishneh Halachot (4:213) says that it is forbidden for the following reasons. 1. By joining the jury one is judging cases according to non-Jewish law and not according to Torah law. This is even worse than being a supplicant in such a court. 2. For a Jew to be on the jury it can encourage other Jews to go to the non-Jewish courts which is a sin. 3. It is considered stealing (gezel) because according to the Torah law, the party may actually warrant a different legal outcome. That is in a monetary case; but in a case of a capital punishment, where the accused could be put to death, it could be even considered murder (if Torah law would not agree with the non-Jewish verdict). 4. Even if the court is judging non-Jews, it is still forbidden to be on such a jury because the court is not judging utilizing the way of the Torah/halachah. One example of this is they would allow women to testify or be on the jury, which is not allowed by halachah. Therefore Rav Klein holds that it is forbidden to be in the jury unless you can save a Jewish life. However, according to Rav Yitzchak Eizik Liebs (Beit Avi 2:144) it is permitted to take part in such a jury. He also holds that one can be a judge in a non-Jewish-- court not only to judge non-Jews-- but also to judge Jews. His reasoning is that the non-Jews have to do seven mitzvot of Bnei Noach and one of the seven is to judge and undertake doing justice. These countries are permitted and even obligated to judge the way they developed their own justice system, and the way they feel is correct. Another point that Rav Liebs mentions in permitting joining a jury is that the jury may not really be judging directly (this may vary from state to state). The jury may only decide with what level of crime the criminal is to be charged with, for example a misdemeanor vs. a felony and that is what they recommend to the judges who make the final decision. The jury doesn't have the last word in what the punishment will be; that is the domain of a professional judge. (it's possible that the Mishne Halachot and the Bait Avi are referring to legal systems that are not exactly the same, and possibly they got information about different states. In any case it doesn't seem that there is a difference in the ruling, and the Mishne Halachot would forbid it anyway and the Beit Avi would permit it anyway.) I saw that Rav Tzvi Hershel Schachter was quoted that he strongly disagrees with the Mishne Halachot and holds that participating in a jury is definitely permitted. Your question is a follow up question to Harav Yaakov Ariel's answer who said that one should avoid participating in a jury for a different reason. He feels that it is a mistaken system where inexperienced people decide matters of life and death. According to what he said, one should not sit in a jury even if it is a case of Jews being the victim and the defendant. Summary: Some poskim forbid joining a jury and some do permit it. Harav Yaakov Ariel is against participating in a jury in any case and did not differ between the litigants being Jews and non-Jews. All the best