I'm not a populist. But I try to present complicated issues in such a way that people know where I stand.

Political leaders need to formulate long-term EU goals that show: Yes, we want to stay together.

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.

Germany is not a fair country. Millions of people believe that things aren't fair in this country. Company profits and bonus payments have increased at the same rate as precarious employment situations.

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.

Donald Trump is betraying everything that made America great: tolerance, democratic institutions and respect for the individual. In that sense, Trump is the most un-American U.S. president that the country has had in a long time.

[Recep Tayyip] Erdogan is an adherent of realpolitik. He knows that international relations are not built on the strength of unilateral demands, but on solutions that are in everybody's best interest.