In establishing the common currency area, the Euro, the separate countries are essentially throwing away this adjustment mechanism.

FORBES: Friedman and Roubini on the Euro Breakup

And for a common currency to work it must be applied across something which is at least close to being an optimal currency area.

FORBES: The Inevitable Failure of the Euro

To some extent, their hopes were warranted: The growth correlation between Germany and other euro-area economies has risen sharply since they adopted the common currency.

WSJ: Troubles in Euro Zone Offer Chance to Fix Its Flaws

Its expansion from 15 members to 25 should create pressure for making the EU what it always should have been--a vast free-trade area with open borders and, for most members, a common currency.

FORBES: The Wilsonian UN--R.I.P

Both the German Unemployment Change and Euro area flash CPI estimates missed their forecast levels and put pressure on the common currency.

FORBES: Euro Climb Stalls On Meager Economic Readings

This decision has the potential to trigger a full-scale bank run across the euro area and such an outcome could place in question the continued existence of the euro as a common currency.

FORBES: Cyprus Depositor Tax: Genius Plan or the End of the Euro?