The political cost
The economic cost is, in many ways, the least of the concerns investors shouldhave about a break-up. Fragmentation of the Euro would incur political costs.Europe’s “soft power” influence internationally would cease (as the concept of “Europe” as an integrated polity becomes meaningless). It is also worth observingthat almost no modern fiat currency monetary unions have broken up without someform of authoritarian or military government, or civil war.
Comment by Adamantine:
We now have a clear idea that there may be a time coming when the EU is truly in turmoil. We also know Catherine Ashton is not likely up to the task of dealing with such a problem. We are suspicious it might require the help of someone who knows where all the missiles are kept.
Thanks to Nonymouse for the link.