Daniel Altman at Foreign Policy writes:
In 1999, the traditionally hard currencies of Europe’s north merged with the softer currencies of the south to form a new money that was somehow supposed to be stronger than any of the ones it replaced. Under the stewardship of the European Central Bank (ECB) in Frankfurt, the euro was meant to — and did — become a reserve currency to rival the dollar. Though the supposedly prudent northern countries didn’t always keep their budget deficits under control, they still managed to survive the worst of the global economic downturn. By contrast, the profligacy of the south, together with its flawed banking systems, has created a hotbed of crises that stretch 2,300 miles from Lisbon to Nicosia.
These crises would have been a lot shorter if the countries involved — Greece, Portugal, Spain, now Cyprus, soon Slovenia, and perhaps Italy for a second time — had possessed their own currencies. But all of them use the euro, so their monetary policy is set in Frankfurt at the ECB. Instead of devaluing their currencies in order to spur exports and ease the repayment of debts, all of these countries have had to undergo some combination of fiscal austerity, deflation, and, most notably in Cyprus’s case, loss of assets.
The lesson is you can’t have monetary union without fiscal union. Monetary policy and fiscal policy need to work together.
The interesting thing is the impact on political stability as well. They have a table showing how Parliaments in southern Europe have become more fragmented and extreme, which threatens Europe as a whole to a degree. They use the Herfindahl Index to calculate the fragmentation.
The NZ Parliament Herfindahl Index is currently 0.34.