Reply #67: Just to clear things up: The Senate did ratify this treaty. [View All]

[Hosnon]

"The United States has signed and ratified the Vienna Convention, a treaty under which the United States has promised, among other things, to inform an arrested foreign national, such as Leal, that he has a right to request the assistance of his country’s consulate. Vienna Convention on Consular Relations (Vienna Convention), Art. 36, Apr. 24, 1963, 21 U. S. T. 77, 100–101, T. I. A. S. No. 6820." 564 U. S. ____ at 2 (2011) (dissenting opinion).

http://www.supremecourt.gov/opinions/10pdf/11-5001.pdf

ETA: The issue was the distinction between a self-executing treaty and a non-self-executing treaty. Non-self-executing treaties require subsequent congressional legislation to implement them.

ETA2: Oops, that line is from the dissenting opinion. Nevertheless, it was ratified.