An Italian Perspective...

 From Mr Salvatore Rossi's speech:  Monetary policy and the independence of central banks - the experience of the European Central Bank in the global crisis

 Mr Salvatore Rossi, is Senior Deputy Governor of the Bank of Italy. 

http://www.bis.org/review/r141209f.htm

"The sovereign debt crisis was a watershed. It made it glaringly clear that the incompleteness of European integration could compromise monetary policy, hindering its transmission between countries and undermining the central bank's functional independence. This for three principal reasons. First, the sovereign debt crisis stirred fears that the euro could break up. An eventuality that until then had been judged to be of probability zero now, in international eyes, entered the sphere of possibility. The consequence, which materialized mostly in 2011, was investors' demand for high premiums on government bonds in the countries of southern Europe. The lack of fiscal union thus came to the fore, and the policy limp could be seen in all its destabilizing potential."
"Second, this resulted in an accentuated segmentation of the European financial market along national lines, marking a brusque regression in the laborious process of integration that had been advancing for a decade-and-a-half..."
"Third, all of this engendered a corresponding segmentation of the banking market. The banks whose balance sheets abounded in the government securities that were under fire in the marketplace were subject to the same fears as their "sovereigns"

"...the political line of reasoning cannot be ignored. The structural reforms in the euro-area countries that have lagged behind in competitiveness, Italy to start with, are vital for two reasons: the first is that they are the only way to unblock the jammed mechanisms of economic development; the second, equally important, is that they help to increase trust among nations. If the present diffidence should put down roots the entire European construction would be in peril."