So that means that when the US decides that something is OK to do that then it is OK for the US to do that.

Canada chose not to play ball this time 'round because there WAS no UN sanction. There is not much open to interpretation. Unless EVERYthing is open to interpretation, in which case your Constitution is up for grabs, your legal structure is totally open to interpretation, and world peace is just another name for Neocon dominance--with the US playing the role of the enforcer. Because what you have said simply means that the US can do what it darn well wants when it darn well wants to do it. Hell, whay didn't you just say so in the first place. Woulda saved lots of time.