Choshen Mishpat 348:2
“Anyone who steals even a minor amount violates the prohibition of [Leviticus 19:11] “You shall not steal” and is required to repay [the amount stolen] whether one steals from a Jew or a gentile.”
Choshen Mishpat 359:1
It is forbidden to rob or to cheat even a minor amount from either a Jew or a gentile.
Kitzur 182:1
It is forbidden to rob or to steal even a minor amount from either a Jew or a gentile.
Mishneh Torah, Hilchot Gezeilah 1:2
And it is biblically forbidden to steal even a minor amount; even a gentile – it is forbidden to steal from him or to cheat him. And if you stole from him or cheated him you must return the stolen money or object.
Sefer HaChinuch, 259
Maimonides of blessed memory wrote that if one lies in his measures and thereby overcharges even to an idolatrous gentile one violates a negative commandment and must return the money. Similarly, it is forbidden to mislead the gentiles in calculating prices as it says [Leviticus 25:50] “he shall make a reckoning with his purchaser” [see below] even if he is subjugated to your authority; even more so if the gentile is not subjugated to your authority and it says [Deuteronomy 25:16] “For an abomination to the Lord, you G-d, are all who do this.”
Bava Kamma 113a-b
And who permits stealing from a gentile [which is implied in an earlier case]? Doesn’t it say [in a baraita]: R. Shimon said that R. Akiva taught this when he came from Zephirin: From where do we know that theft from a gentile is forbidden [Leviticus 25:48] “After he [a Jew] has been sold [as a slave to a gentile] he shall have a redemption.” We see from here that the Jewish court cannot take him away and he will leave his gentile owner. Maybe [after being redeemed the Jewish slave will go free and] the gentile will have to collect his money on his own – therefore it says [v. 50] [between this teaching and the earlier case]. Here [in this teaching] we are speaking about theft and here [in the earlier case] we are speaking about annulling a loan.
Tosefta Bava Kamma 10:8 “It is worse to steal from a gentile than from a Jew because of desecration of [G-d’s] name”
Mishneh Torah, Hilchot Geneivah 1:1, 7:8, Hilchot Gezeilah 1:1; R. Yechezkel Landau, Noda BiYehudah I Y”D 81; R. Yom Tov Algazi, Hilchot Bechorot 2:17; R. Chaim of Volozhin, Responsa Chut Hameshulash, 14, 17; R. Ephraim Navon, Machaneh Ephraim, Hilchot Gezeilah, 3; R. Yair Bachrach, Chavot Yair, 79; R. Tzvi Ashkenazi, Chacham Tzvi, 26 all state it is a deoraysa
(thank you to gil student’s http://www.angelfire.com/mt/talmud/theft.html for these mekoros)
in addition there is the issue of dina dimalchusa dina, which means that even if for some reason it was muttar to steal, it would still be forbidden due to american law. furthermore there would be a tremendous chillul hashem entailed. the meiri states (this one i dont have the mekor in front of me) that modern day religions do not have the status of akum and therefore one is obligated to return their property just like a jews etc. ) furthermore there is a principal that if a non-jew is obligated in something from the sheva mitzvos we are also obligated, and non jews cannot steal from eachother based on the sheva mitzvos
kol tuv
– gavi