So yes, actually, it is. On the front page. Explicitly.
That's why treaties trump national law in the first place.
American courts are fairly hostile towards treaties (something which I think is under the surface of Medellin). Basically treaties are un-democratic. They are written by unelected diplomats and are necessarily the product of foreign influence. It doesn't help that one of the motivating factors for the treaty provisions of the U.S. Constitution was the status of the U.S. as a precarious winner of the Revolutionary War. One of the conditions of the Treaty of Paris was that debts on both sides would be recognize. Of course, in most cases Americans were the debtors. The British were very concerned about states passing laws to abolish debts owed by their citizens to the British. Hence the provision elevating treaties of the U.S. above state law.
http://en.wikipedia.org/wiki/Bricker_Amendment#Legal_backgro...
The key here is that the 'last bit counts'.
Missouri v. Holland, nor any subsequent case of which I'm aware, did not disturb the holding of the Cherokee Tobacco Case ("The Supreme Court decided against the men, stating that a law of Congress can supersede the provisions of a treaty."). See: http://law.justia.com/constitution/us/article-2/18-treaties-... ("Treaties Versus Prior Acts of Congress.—The cases are numerous in which the Court has enforced statutory provisions which were recognized by it as superseding prior treaty engagements.")
Another thing that led to the status of treaties in the U.S. is that the Court spent much of the 1800's looking for ways around the various treaties the U.S. entered into with the Indian tribes.
Treaties are dangerous and anti-democratic. They put legislative powers in the hands of diplomats. They represent the words of a man binding a nation of people. Europe is learning this the hard way, with ACTA, etc.
If all you have is the internal laws of countries and no international framework to work within then you are actively advocating for isolationism and war.
Just so you realize where that reasoning leads to.
It would be rogue if it decided to, say, give crucial information to a foreign country at the expense of the United States.
But what does that make us? Are we now the bitter EX of the US?