NATO says so
“ NATO says so”
Correct.
They are their own authority.
They can change their charter or violate it.
One can say they are hypocrites if they do etc…
By the way, for the sake of discussion I did not point out that NATO says it is more than a defensive alliance.
“ They are resolved to unite their efforts for collective defence and for the preservation of peace and security. They therefore agree to this North Atlantic Treaty :”
Preservation of peace and security is also there.
Nonetheless, for our discussion on authority that didn’t matter.