There are certain reactions that you aren't allowed to show in Berlin, for example that you feel offended. If you do, the best-case scenario is a sympathetic article along the lines of: Nice guy, but he's not up to it. The alternative is to don a suit of armor and become cynical. But that's not healthy either: Cynicism is the worst characteristic a politician can have. That's why you have to have an internal balance in Berlin, so you can stay true to yourself. And I have that.

Donald Trump has made the principle of purposely breaking a taboo into a means of achieving his political objectives, which is something that he has in common with Turkish President Recep Tayyip Erdogan and Hungarian Prime Minister Viktor Orbán. Trump systematically violates international rules. But we cannot allow ourselves to forget that Trump is not the U.S.

The quota idea is a good one, but there are two problems with it. The first is clear: A quota system would also require all European countries to be prepared to take refugees. And secondly: What happens when the quota has been filled? Would we then simply tell those who are threatened, sorry but we have to send you back?

We are seeing now that without the contribution of the Social Democrats, Germany cannot be governed. We are a proud and self-confident party. We should now act based on that pride, and not out of fear.

I'm proud of the fact that Marine Le Pen in France insults me and Geert Wilders in the Netherlands calls me his opponent. The way I see it is, if these people weren't attacking me, I would be doing something wrong.

It is impossible to swear an oath to the German Basic Law without realizing that our constitution is among the most liberal constitutions in the world. As the head of government in such a country, I would stand up to all those who call into question this free, open and tolerant model of society.

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.