Europe is difficult to coordinate, and our main deficit may not even lie in this area of finance and economics, but in foreign and security policy. We have a leadership problem because we are still 27 different members who have still not decided on how to work with each other based on what we used to call a European constitution.

One has to explain to people that the EU in this form is the answer both to 1945 and to the 21st century, in a dramatically altered world with new heavyweights, and that Germany benefits from the continued integration of Europe in political, economic and societal ways. And, of course, that means the Germans will have to pay.

When I look at the chaotic and volatile debate right now, both in Germany and around the world, my impression and concern is that the daily barrage of proposals and political statements is making markets and consumers even more nervous. Still, Brussels is pressing for a joint European approach.

There's no more place in the euro zone for well-meaning laxness when dealing with deficits and failings. If the demands on Greece aren't taken seriously, we'll get stuck in quicksand. In the worst case, this would make it acceptable for one tranche to not be paid out. It is in the Greeks own interest not to test that.