It became obvious that we had completely failed to impose rules on unbridled speculative capitalism. That destroyed financial systems, hollowed out state systems and deeply shook German social stability. Can you recall the debate about "locust" hedge funds - even if it's a terrible term. The speculator capitalists roamed the land, stealing the substance from companies and throwing away the shells. And we were powerless.

There are surely people in London who would love to play us off against each other. That would be disastrous for the EU.

If we want to defeat Islamic State, we first have to arrive at a cease-fire agreement in Syria. Once that has been achieved, an anti-IS coalition can be assembled, including Russia, Saudi Arabia and Iran. That, however, will be significantly more difficult in the wake of Turkey's downing of the Russian plane.

In political life, it is extremely difficult to remain loyal to a friendship when constellations of power or interests are in the way.

Complementing the nation-state as it reaches its limits amid globalization: That is what Europe must offer.

Businesses will only invest in Greece if three conditions are fulfilled. First, there must be a clear commitment to the euro. No businesses will invest if they have to fear that Greece will leave the euro zone at some point. Second, the Greek government must be prepared to work together with European institutions in order to restructure the country.

One of the richest and largest markets in the world, Europe can set global standards. And if a French president is prepared to at least consider clear rules in the Eurozone, then it would be fatal if Germany were not to react.