Should Foreign Law be Cited by the Supreme Court?

So, in an opinion piece in the Wall Street Journal today, there is an argument that citing foreign law by the Supreme Court is not wrong. Well, I have one question about that. If you allow foreign law, how do you choose what foreign laws? I ask this because the story referenced the Texas Sodomy case. If we were to consult foreign law, I guess it wouldn't be illegal to be homosexual in France, but what about in Iran? Don't they kill gays as soon as they know they are gay? So which law takes precedence? (I picked those two countries because neither actually are that similar to the U.S.) I am just wondering here.