The crash of 2008 revealed the flaw in the euro’s construction, as each member country had to rescue its own banking system instead of doing it jointly. The Greek debt crisis brought matters to a climax. If member countries cannot take the next steps forward, the euro may fall apart, with adverse consequences for the EU.
Check out the full article here.
And while you are at it, have a look at Krugman’s column, The Making of a Euromess.