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

When we were negotiating the ongoing financial period in 2013, I talked myself hoarse. London and Berlin in particular insisted on reducing the budget. So we - to the applause of German journalists - made cuts to central future-oriented areas and slashed the budget for development aid, research and technology.

It was clear to me that the White House's solemn atmosphere would not civilize Trump. But the merciless nepotism with which he conducts politics, in which he places himself and his family above the law, I wouldn't have considered that possible. And on top of that there is this reduction of complex political decisions to 140 characters. When it comes to a U.S. president, I consider the reduction of politics to a tweet to be truly dangerous. Trump is a risk to his country and the entire world.

We have to engage in a dialogue with Donald Trump because he is the elected president of the United States of America. But we have to emphatically oppose his foreign policy ideas.

The Social Democrats have to listen to people who are attracted to the AfD party. That isn't a mistake at all. You can also win them back. Of course, there are a lot of angry voters who are ideologically charged. But there are also a lot of quieter voters who plan on voting AfD to send a message. We can never give up on them.

Solidarity is the fundamental idea of European cooperation. If a country feels itself to be militarily threatened and calls for soldiers, weapons and sanctions, then that's what it gets. When governments say they need money from the structural funds to stabilize their economy, that's what they get. But you can't cherry pick solidarity.

I try to speak in a manner that allows people to tell me apart from my political adversaries. And I speak in a manner that the people can understand. For me, that isn't populism.