I guess we may soon see how strong this law is.
Separation of Powers and NATO Withdrawal, 2023:
"In 2023, Congress enacted a law that prohibits the President from "suspend[ing], terminat[ing], denounc[ing], or withdraw[ing] the United States from the North Atlantic Treaty"—which established the North Atlantic Treaty Organization (NATO)—without the advice and consent of the Senate or an act of Congress."
