The associated debt build-up led to the sovereign debt crisis earlier in 2010 and the spreads on this debt indicate that the markets are not convinced that these issues have been fully resolved.
This suggests that in order to have viable economic and financial integration, there may be a case for a single fiscal authority, in the same way that there is for a single central bank. Such a move, however, is likely to be far more politically sensitive than reaching agreement on a common monetary authority.