We Germans are particularly aware that you can only be successful on the global market over the long term if you offer energy-efficient products that are, by nature, climate-friendly.

We need a big debate in society about how we are going to shape Europe and tame capitalism. A government must provide direction and make concrete proposals. It is one of Angela Merkel's biggest failings that she doesn't do this.

At the end of the day, men like Donald Trump need to be given that which they themselves dispense: clear messages. I would confront him as clearly and explicitly as possible. It is not only the right, but also the duty, of the leader of a German government to do that.

Would I sacrifice a friendship to take a step forward in my political career? Thus far in my political career, I have been spared from having to make such a decision, thank God. And I can't imagine what it must be like.

If cooperation among governments were the superior concept for progress in Europe, I'd be onboard immediately. But the problem is that cooperation isn't working.

Primary responsibility for Brexit lies with British conservatives, who took an entire continent hostage.

Keeping quiet and letting the others do the talking. That may be Angela Merkel's method, but it's not mine.