Já todos ouvimos dizer que uma união monetária sem uma união política está condenada (veja-se a Zona Euro). Será mesmo assim? António Fatas argumenta em Financial crisis, the euro and the need to political union que essa conclusão não é nada óbvia, e que a crise recente da Zona Euro não tem directamente a ver com a falta de um orçamento comum. Vale a pena ler (e, se gostarem, reler o velhinho Is a monetary union without a fiscal union doomed?).
There are plenty of example where the European Union (EU) requires some serious political consensus: the EU requires partial transfers of sovereignty to a supranational authority when it comes to legislation, the EU has economic mechanisms that imply a significant transfer of income across countries (via its budget, the structural and cohesion funds). Then why is it that the EU does not require to be backed by a political union in the same way the Euro project does?
The euro facilitated flows across countries as exchange rate risks had disappeared and provided the illusion of no risk. Second, once the flows had taken place it created financial links between banks and governments across countries that made them exposed to the same risk. In addition, the ECB because its connections with banks became a central repository of that risk and a solution for some of the countries facing a credit crunch — the ECB acted like the IMF in many ways.
None of this is exactly about monetary policy, even if the ECB is involved. This is about financial risk and how financial crises have painful economic consequences. When sharing a currency the risk of financial crisis and its potential solutions bring countries and governments together in a way that a political consensus seems to be necessary because transfers might be involved and because common political solutions need to be found. And while these transfers might be smaller than the ones agreed as part of the Social and Cohesion Funds of the European Union, they come as a surprise and they are uncertain (we cannot agree ex-ante on their final size). This is what makes the Euro project a much more difficult one to manage without a sense that we all belong to the same group and are willing to work on this together.
For many, the Euro was one of the projects within the much bigger ambition behind the European Union (which came with the idea of a partial political union). But the recent financial crisis has shown that the risks associated to sharing a currency when financial and sovereign crises are possible, are a lot larger than what we thought. And these risks are much larger than the risks associated to simply sharing the same currency and the same monetary policy (yes, one interest rate does not fit all but this is not the real issue this time).