Goodbye Schengen

"Europe has forgotten that history is fundamentally tragic," said Manuel Valls, the French prime minister. "If Europe can't protect its own borders, it's the very idea of Europe that could be thrown into doubt. It could disappear - not Europe itself, not our values, but the European project, the concept we have of Europe, that the founding fathers had of Europe."

The European Union - 28 countries and 500 million people - is not really going to disappear just because it cannot agree on how to deal with one or two million refugees. But one of the great symbols of its unity, the Schengen Treaty that allowed its citizens to move around without passports or border checks, is being suspended - perhaps forever.

Schengen doesn't cover every single EU country. The United Kingdom and Ireland remain outside the Schengen Zone, and Croatia, Romania, Bulgaria and Cyprus, all new EU members, are still waiting to join. Switzerland, Norway and Iceland are part of the Schengen Zone although they are not EU members. But it does include over 400 million people.

It is a remarkable achievement. You could get into your car in Portugal and drive all the way to Finland via Spain, France, Germany, Poland, Lithuania, Latvia and Estonia without ever once having to show a passport or identity card. There would not even be anybody in uniform standing at the frontier to wave you past, just a sign by the side of the road saying "Welcome to (Country X)."

Or, rather, that was the situation until last month, when Germany, Denmark, Sweden and Austria re-imposed passport checks at their borders, ports and airports even for travelers arriving from other Schengen Zone countries. France acted even earlier, declaring emergency controls on its borders after the terrorist...