Donald Trump is withdrawing from the Paris climate agreement because he wants to lower environmental standards for American products and manufacture more cheaply. His reasoning is quite simple, but very shortsighted. It won't succeed because, by doing so, Trump is missing a golden opportunity to modernize American industry.

I believe that the majority of people in Europe want to demonstrate solidarity with the refugees.

Businesses will only invest in Greece if three conditions are fulfilled. First, there must be a clear commitment to the euro. No businesses will invest if they have to fear that Greece will leave the euro zone at some point. Second, the Greek government must be prepared to work together with European institutions in order to restructure the country.

At the time, Jean-Claude [Juncker] was already an important man in Brussels. I was a young representative in the European Parliament. We talked for a long time and from that point on, our connection became increasingly deep. But our working-class origins are at least as important to our bond.

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.

I want to end tax dumping. States that have a common currency should not be engaged in tax competition. We need a minimum tax rate and a European finance minister, who would be responsible for closing the tax loopholes and getting rid of the tax havens inside and outside the EU. It is also clear that we have to reach common standards in our economic and labor policies. We cannot continue to just talk about technical details. We have to inspire enthusiasm in Germany for Europe.

We are living through an epochal shift. If we aren't careful, the elementary foundations of our pluralistic democracy will be threatened.