Justice Black declared: “neither the cases nor their reasoning should be given any further expansion. The concept that the Bill of Rights and other constitutional protections against arbitrary government are inoperant when they become inconvenient or when expediency dictates otherwise is a very dangerous doctrine and if allowed to flourish would destroy the benefit of a written Constitution and undermine the basis of our government”.
While I agree that this case could be construed as to your assertion, with the court that we now have, I’m not so sure that this case would surfice as a defense... just saying. Did this case involve an agreement or a treaty?
Reid v. Covert is not just a case. It is THE landmark case on the supremecy of the Constitution over treaties.
Here is what the Court wrote: (my bold)
P.17 - There is nothing new or unique about what we say here. This Court has regularly and uniformly recognized the supremacy of the Constitution over a treaty.*fn33 For example, in Geofroy v. Riggs, 133 U.S. 258, 267, it declared:
P.18 - This Court has also repeatedly taken the position that an Act of Congress, which must comply with the Constitution, is on a full parity with a treaty, and that when a statute which is subsequent in time is inconsistent with a treaty, the statute to the extent of conflict renders the treaty null.*fn34 It would be completely anomalous to say that a treaty need not comply with the Constitution when such an agreement can be overridden by a statute that must conform to that instrument.