Germany must continue to champion the world's biggest free single market, and under its leadership, the EU can overcome its internal differences.

The largest weight is now on Germany's shoulders. Chancellor Merkel must continue to convince people of the EU's importance; she must spearhead the effort to redefine the EU. In order to do this, Germany must become a muscular democracy. It needs to shoulder far more responsibility for the physical security of Europe, especially Eastern Europe and the Mediterranean. So far, unfortunately, Germany has taken the lead in disrespecting Europe's borders by opening its doors to more than a million refugees and migrants.

The pacifist streak in German politics is a problem. But Greens and Social Democrats have to ask themselves: In an imperfect world, what do they prefer? The rise of the right or the success of the European project?

Germany must continue to champion the world's biggest free single market, and under its leadership, the EU can overcome its internal differences.

German dominance in the EU is a fact of life. But for historical reasons, it would be the last country to be swept away by a populist wave. And one thing is certain: If Germany goes down, Europe goes down, and with it all the values which we thought are worth living for. Germany has to be the champion of these values.

If there ever was a time for a cool, rational and unemotional series of responses on the part of people in Europe, it is now. One reason is that Russia's President Vladimir Putin and Trump are very similar: They are macho types, they are bullies - and they want the same thing: to weaken the EU, albeit for different reasons. Trump, for his part, is a protectionist of the first order, and he wants to make his vision work. He shows no interest in competition with others, but aims to go back to the 1930s.

We are in an extremely dangerous situation. It was ignorant and ahistorical for Donald Trump to say that the EU will dissolve. He is a man of very little historical understanding. For example, when he accused his own intelligence community of using Nazi tactics against him, he was actually confusing the Nazis with East Germany's secret police, the Stasi. Trump also has no idea that for 70 years, it has been U.S. policy to support those who want to unite Europe. It is very dangerous that he is turning his back on Europe now.