Secession is the only real hope. Maintain the free trade and common labor market, but get rid of the Euro and leave the political sphere. Losing your sovereignty to a national government is bad, but getting it lost to a multi-national government is even worse.
I have tried to find something about this in the literature section but couldn't do it. In a Libertarian society: What happens if somebody (Mr. A) is denounced by another one (Mr. B) as a criminal, but Mr A isn't affiliated to any security or justice agency and he won't comply to go to trial...