The euro zone was driven by the neoliberal view that markets are always efficient. That in itself is political. There was no pressing economic need that the euro was required to solve, but leaders believed that it would foster growth.

A single currency entails a fixed interest rate, which means countries can't manage their own currency to suit their own needs. You need a variety of institutions to help nations for which the policies aren't well suited. Europe introduced the euro without providing those structures.

In the end, the politics of the euro zone weren't strong enough to create a fully integrated fiscal union with a common banking system, etc.

Joseph Stiglitz Quotes