Well, why not? If the EU is this fantastic trade organization it should make a great defense organization, too. In fact, a European Defense Force wouldn't necessarily fall under the the auspices of the EU. Why the hell should the United States spend billions and billions of dollars protecting a bunch of small principalities who won't even spend 2% of their own GDP to defense themselves? If Europe wants to stack forces on the border with Russia have at it. But the U.S. taxpayer should not pay for it.