Yesterday's shining heroes of Brexit have become the sorrowful heroes of today.

I have another explanation [of Brexit]: In its 43 years of EU membership, Britain has never been able to decide whether it wants to fully or only partially belong to the EU.

In politics, there are different categories of friendship. My friendship with Greek Prime Minister Alexis Tsipras, for example .

I would describe that [friendship with Greek Prime Minister Alexis Tsipras] as a utilitarian friendship. At the time, his country was facing the prospect of leaving the euro zone and many Greeks felt abandoned by Europe. In such a situation, it seemed appropriate to me to present myself as a friend to Greece. It had to do with the country's dignity.

One shouldn't pursue the wrong policies just because one is afraid of not being reelected. Those who intend to govern have to take responsibility for their countries and for Europe as a whole. This means, if need be, that they have to pursue the right policies, even if many voters think they are the wrong ones.

Greeks have to know that they are not alone ... Those who are fighting for the survivor of Greece inside the Euro area are deeply harmed by the impression floating around in the Greek public opinion that Greece is a victim. Greece is a member of the EU and the euro. I want Greece to be a constructive member of the Union because the EU is also benefiting from Greece.

I am chilled by the realization of how similar circumstances in Europe in 2013 are to those of 100 years ago.