Can the U.S. make a treaty with an organization that is not a nation? And without Senate ratification?
I know a treaty cannot supersede the U. S. Constitution or Bill of Rights.
Yes. And of course, there would be other nations signing it as well. But from what I’ve seen argued about the alleged unwritten promise made by James Baker back in 1990 regarding NATO expansion, we would be bound to the WHO agreement even if it isn’t ratified, and even if it is only a verbal agreement.