Charles S. Maier is a professor of history at Harvard.

EUROPEAN leaders seemed to understand, at least until recently, that even a partial breakdown of the euro zone would have a devastating economic and political impact on departing countries and on the European Union as a whole. But while they have repeatedly committed to providing emergency aid, they haven’t yet accepted that saving the euro is more vital than clinging to the constraining rules that govern the European Central Bank. They are debating their future with a diminished sense of history and of the alternatives available to them. They should recall Secretary of State George C. Marshall’s grave warning, upon returning from Germany in early 1947: “The patient is sinking while the doctors deliberate.”

The former patient is now the principal doctor. The German chancellor, Angela Merkel, assures us that the answer to the crisis is “more Europe” — more coordination of policies and more common decision-making. But the question behind the immediate crisis posed by Greek and Spanish debt is how to bring about more Europe. It will not be created simply through the European Union’s recent “fiscal compact” extracted by Berlin, which provides for automatic but unenforceable fines designed to encourage budget orthodoxy....