[ilgipper]

So they have sovereignty to conduct their defense regardless of what they're allies recommend, but when we want to go out in the world to defend our citizens from terrorists and tyrants we must first get the world's approval?

[gcruse]

 when we want to go out in the world to defend our citizens
from terrorists and tyrants we must first get the world's approval?
 

If, when you say 'defend' you mean pre-emptively invading
countries you declare to be tyrannies, it helps to have at
least a tacit approval as fig leaf for naked aggression.