The Soviet Union was, by the 1970s and 1980s, relatively stable and predictable. Putin's Russia is much more volatile. Nuclear policy is really in the hands of one person, or a small group of people, instead of a huge party-state apparatus. The possibility of a mistake is greater now.

Putin imagined it would be different. So, like many Russian leaders before him, he imagined that Ukraine was basically Russia, but they speak with a funny accent. Actually, it's not Russia; it has a different identity. It has a very different language. Russians don't automatically understand Ukrainian. And, in particular, the way Ukraine has developed over the last two decades is different from the way Russia has developed.

I believe democracy can survive. But it's certainly true that the euphoria of the 1990s - an era when democracy was spreading and more and more people found it attractive - has ended. Trump is not a cause but rather a symptom of this change.

A lot of the Russian economy is built around people who are one way or another milking the state and taking money from the state and recycling it into their private bank accounts. And there are a lot of people who are taking advantage of that, so it's not just one person. It's a kind of web of people doing that, and that's how the system stays in power and how people stay in control.

Navalny is a blogger-turned-activist, but he finds stuff and he puts together these very, very clever, very high production value videos which underline the corruption at the top of the system, and there are millions of people who watch them. Some people think he must have some kind of protection inside the system because he hasn't yet been completely put out of commission; he's allowed to go on. He himself has said he wants to run for president.

Putin has made life difficult for a lot of Russia's richest men; they don't like the sanctions; they don't like the war with the West. Many of them have houses and families and businesses in the West, and so I can see them being unhappy. But at the moment, the political system is so constructed that it would be very difficult for them to leave. That's not saying it couldn't change.

The Soviet Union was, by the 1970s and 1980s, relatively stable and predictable. Putin's Russia is much more volatile. Nuclear policy is really in the hands of one person, or a small group of people, instead of a huge party-state apparatus. The possibility of a mistake is greater now.