There is nothing in all of European politics that says to a politician “You have made it” more than the walk down the red carpet at the beginning of a European Union summit. The perambulation sweeps a broad arc through the vast, light-filled atrium of the Europa building, flanked by the flags of all the member states of the EU, turning gradually all the while leftward (read into that what you will), past the wall – perhaps some 30m long – of snapping cameras and outstretched microphones. The leaders of Europe’s sovereign governments, accompanied maybe by a flunkey or two,...