I don't think you quite understand what I was saying. Free trade is the problem, not the solution. Germany makes a lot of stuff and sells it to the southern countries, running huge trade surplus. The southern countries borrow to buy the stuff and eventually have debt problems. There is no mechanism to get money from Germany back to southern Europe in the amounts needed. Before monetary union, Italy or Greece would see their currencies go down and the trade deficit would start to balance out.

In the US the people in rich parts of the country pay more in taxes to the federal government than they get back. This is a good thing, not a problem like many people state. It is not about building weapons for export, it is that the US government spends $600 billion on defense spending, moving resources from rich parts of the country to the poorer parts (to pay for government bases and defense contractors that build weapons for the US government). I agree that there are better ways to do this redistribution of wealth, but it is the only one that seems acceptable to the Republican party. Building infrastructure could be another, but it has not happened since the building of the interstate system ended in the 1980's.

The EU supra-national government (very similar to the US federal government over the US states) has a very small budget (€143 billion for the year 2014, from Wikipedia) and no real ability to raise large amounts of money from taxes it can impose. Varoufakis believes that until the EU has such a mechanism, having a common currency is going to continue to build up financial problems that are like to break up the union in a bad way.