Vladimir Putin is the wealthiest man on the planet, for sure. But this is different to the wealth of a Bill Gates or a Warren Buffett, a Carlos Slim or a Sergey Brin. They stay wealthy whether it is Barack Obama or Donald Trump in power. Putin's wealth depends on him staying in power. It is all about controlling the budget, the hard currency reserves and keeping under his thumb the oligarchs who cannot move their money without his permission. It is something close to a trillion dollars that he can control and move.

There is no doubt that [Vladimir] Putin is responsible for this crime, whether or not he gave the order to commit the murder [of Boris Nemtsov] himself. Putin created the conditions and atmosphere that have made this kind of thing possible.

I say we should praise Donald Trump for existing and for winning, because it has woken people up. For many years, I have been trying to say to Europeans, and especially to Americans, that Vladimir Putin is a problem for the world. And they have swatted me away. "It's your problem, we have our democracy." Suddenly, because of Trump, they are learning about separation of powers, independence of the judiciary and that Ronald Reagan was right when he said, «Freedom is never more than one generation away from extinction».

[Romans] never made any improvements on the cavalry. And amazingly, when you read the sources, they couldn't make it because stirrups were not known in Europe. For hundreds of years, the Romans couldn't make a cavalry which proved to be extremely effective.

We are living in a new ice age, and we need to apply the recipes of the Cold War to the Kremlin. That means isolation instead of offers of negotiation. And Ukraine should have been supplied with weapons long ago.

Learning from our mistakes is critical for improving, but even I don't have patience for ranking my regrets. Regret is a negative emotion that inhibits the optimism required to take on new challenges. You risk living in an alternative universe, where if only you had done this or that differently, things would be better. That's a poor substitute for making your actual life better, or improving the lives of others. Regret briefly, analyze and understand, and then move on, improving the only life you have.

The legend of the best player of chess has been destroyed.