Not that they care about the Constitution and you are of course correct. However they are basing this on the fact we already entered a treaty when we joined the UN. Their argument will then be that they are bound by it because the the UN treaty and Charter for all members.

But see, there is more to the WHO than what we see right now. They have already declared guns an international health crisis. Think of it... There is no way in hell America would accept chips or the mark of the beast unless they have no way to defend themselves. Guns first, total control second