I would have oriented myself in case of Donald Trump according to what former German Chancellor Gerhard Schröder said to then - U.S. President George W. Bush when the Americans launched a war that was in violation of international law. Schröder showed that a German chancellor can act in a clear and self-confident manner toward a U.S. president.

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.

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.

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.

Ms. Merkel is avoiding retirement issues. She simply doesn't want to do anything, although she knows that doing nothing means that real pensions will fall. That is preprogrammed old-age poverty. When it comes to wage fairness: It was Ms. Merkel herself who blocked the establishment of a right to return to a fulltime job after going part time for a period. Yet everyone keeps saying that our platform is identical to that of the conservatives. It's crazy.

I have friends in politics who really put the friendship to the test through their behavior.

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.