In order to understand why the euro has been at the epicentre of the global crisis the key concept to keep in mind is the concept of a commitment device. The euro is a commitment device whereby member countries increased the cost of policy laxity with the intention of obtaining the benefits of enhanced credibility that policy would be disciplined.
Unfortunately, the discipline was nevertheless not maintained, and the commitment penalty has been correspondingly severe. BIS central bankers’ speeches  3  Let us recall that the euro was set up after 30 years of debate on how to reduce the disruptive impact of divergent monetary and exchange rate developments, including numerous devaluations, on real trade and investment integration in Europe.