That's not what kept the peace and there wasn't "peace".
While it is good to debate the Europeans, it is not neccessary to wait for their agreement. It might also be pointless since I'm not convinced the whining of European journalists or leaders of coalition governments really represent average European opinion, anyway.
If a rabid dog needs to be killed after it bit someone, it needs to be killed whether the world agrees with it or not...otherwise it can still bite. Having a mob determine it is OK will not make it more acceptable nor more neccessary than it already is to kill the dog. And having the mob oppose the killing won't cure the dog.
Unanimous consent or majority consent isn't what makes actions acceptable. Such consent is only neccessary when you have your own doubts and need reassurance, or when you desire to make others 'feel good' in case you might need them for something else in the future. If someone isn't potentially useful, their opinion is less relevant. So for some, their blessing might be worth obtaining, provided it doesn't interfere with the goal or slow down the timetable.
An accurate observation of a crucial factual misrepresentation in the article. There is no point in "engaging" European politicians that believe that states like Iran, Iraq, North Korea, Zimbabwe, Somolia, ect. (incomplete list) or their leaders deserve respect, consideration or deference.
The U.S. should simply inform them that the U.S. WILL be nationally sovereign, and act in the best interests of the U.S. and its citizens. Any attempt to oppose this will be dealt with. The Euros can get on board now or when their Muslim immigrants force their hand, their choice.