The British referendum on its membership in the European Union has reignited a debate, not only about the United Kingdom's role in Europe but also about the present, and the future, of the union. Euroskepticism is on the rise across the Continent, and the bloc's leaders, hampered by their own diverging views on how Europe should be managed, seem unable to stop it. Meanwhile, supporters of the "leave" and "remain" camps in the United Kingdom, despite their opposing opinions, agree on one basic point: Attempts to federalize the Continental bloc are doing member states more harm than good. But at other points in Europe's history, federalism seemed to be the answer to healing the Continent's wounds....