As the New York Sun puts it,

A federal appeals court panel yesterday upheld the government's authority to punish Americans for patronizing child prostitutes overseas.

I think the majority was right to hold (over Judge Ferguson's dissent) that this was within Congress's Foreign Commerce Clause power, and I said this to the reporter; but I was a little amused about how the quote was rendered (quite accurately and in context, I should stress, but nonetheless with an odd double entendre):

Mr. Volokh rejected Judge Ferguson's argument that an American paying for sex abroad hasn't engaged in international commerce. "That's quintessentially commerce with a foreign nation," he said.

Let me just state, for the record, that I think it's the paying that makes an American citizen's prostitution transaction with a foreign citizen in a foreign country "foreign commerce." (I understand "commerce with foreign nations" to include commerce with the citizens of foreign nations, at least when the commerce is itself in a foreign place, and not just with the foreign nations' governments.) I do not think that it's the sex itself that qualifies as commerce — or for that matter as a violation of the Non-Intercourse Act.