Well, there are always the necessary formalities, aren't there? One must put clean curtains on the windows and one must whitewash the fence to remain "respectable". Lawyers are handy for that sort of thing. So is money. And power. You can get "authorization" for something if you have enough pull. That will satisfy the tenets of "the law", but it won't necessarily make what you are doing right.

As for closed ranks (between various allies)...well, those often tend to start fracturing apart if things don't go as well as might have been expected. Sometimes a participant will even change sides during a conflict...several of Germany's formerly quite willing European allies declared war on the Germans late on in WWII. They were making a pragmatic decision, based on their own immediate survival interests.