mgd:-
the European Union, in its drive to form a United States of Europe, will slowly pull itself apart, and when it does, history suggests it won't be pretty.
Hammer, nail, head! A European Army (Surely that should read a EU Army?) will be concerned with defending the European Union, not from without but from within. That could range from Internal Security to full outright Civil War. Neither will be pretty as you say. In the former they kick in your door at 0300 hrs, in the latter there will be a mass blood bath, and all because of some bright idea to avoid future European Wars. Oh, the irony!