The rights of US citizens should be the foremost concern of a US legislator and when it comes to satisfying a treaty compromising those rights the treaty or international precedence should be thrown out the window.
Article VI of the Constitution explicitly disagrees with you: "[A]ll Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding."
In other words, the sovereignty was explicitly sacrificed when the treaty was entered into-- and that's the way the Framers intended it.