IIUC one downside of the European monetary integration is that if, say, the German economy is doing fine while Italy is in recession, then Italy cannot simply l

IIUC one downside of the European monetary integration is that if, say, the German economy is doing fine while Italy is in recession, then Italy cannot simply loosen up its currency to boost demand while Germany keeps its currency tight. Instead, the ECB has to either keep the euro tight, screwing Italy, or loosen it, screwing Germany. And since other pan-European political institutions are not as strong as the US Federal Government, setting Europe-wide economic policy for everything other than currency is difficult. The upside of the euro may be greater than the downside, but it seems to me that a new global reserve currency would be mostly downside, for this reason. Then again as a US citizen I have a vested interest.