It was the Americans — with the Marshall Plan, and then NATO — who laid the groundwork, but the E.U. has helped to give Western Europe its most peaceful 60 years since records were first kept. Here's the big picture: France and Germany had fought a war in each of the three generations before the Treaty of Rome. Twice Europe's wars had sucked in the rest of the world. By locking together economies, societies and political structures, the E.U. has made such horrors unimaginable. For that alone, give thanks.