It’s easy for Merkel to insist that Italy has to strictly follow EU rules since she doesn’t have to win an Italian election.
The Euro just seems like a complete failure. Giant economies are limping along with 20% unemployment, unable to recover 8 years after the recession. In contrast the US has managed an OK recovery, now closing in on full employment.
The problem is that each EU national leader is accountable only to voters in their own country. When countries have opposite interests there’s no good way for resolving the disagreement.
The only way it could work would be if Europe-wide economic policy were made by the European Parliament so that taxation and bank regulation would be made coherently across the continent by accountable representatives. But voters, probably correctly, want to maintain national control. But that makes the shared currency a noose.