When you force countries to forfeit their sovereignty for the sake of the union, you force them to surrender power that comes with it. That includes control of their economy, and of course, immigration. Many countries are fed up with the direction of both, and a reasonable person could understand why (even if they disagree) - characterizing that as nationalism or xenophobia, are left wing oversimplifications. The very same ones that cost them the election in the states, and have the democratic party in flames. Regardless, the change in average citizens feelings on these matters are what give someone like Le Pen a very real chance of election. If she, and individuals like Geert Wilders of Holland should win (I suggest Le Pen will), it will likely speed up the slow death of the EU.