Constitutionally, Putin has arranged it so he can stay until 2036, when he’ll be around 84.
He’s in his 26th year in power now, but “like all dictators”, he doesn’t have a successor outside the family lined up.
“If Putin dropped dead tomorrow, he won’t be succeeded by a nice man,” Clarke says.
And there are two things to be nearly certain of – he will be a man and there is likely to be a period of chaos.
Clarke points out Russian history over the past 100 years has seen a strong leader precede “chaos” as the next in line is decided.
That was the case after Lenin and Stalin, right up to the fall of the Soviet Union.
Dictators typically keep “everyone in-fighting below you”, so when they “drop dead” or have the “knife in their back”, everyone fights among themselves to take over.
“You’d expect that to happen again,” Clarke adds.