The sad irony of all this is that the E.U. was built to prevent the very kind of nationalist fervor its economic mismanagement and political heavy-handedness are provoking now. The dustbin of history exists for a reason.
And yet, and yet. It's easy for a generation that has only known peace and relative prosperity to forget that the arc of the political universe is long, and it bends toward wherever you point it. If that's toward chauvinism and isolationism, well, that's what you'll get.