Putin biographer Philip Short, yesterday in the Guardian, explains why Putin invaded Ukraine - please take note, people

'Why, then, did Putin stake so much on a high-risk enterprise that will at best bring him a tenuous grip on a ruined land?

'At first it was said that he was unhinged – “a lunatic”, in the words of the defence secretary, Ben Wallace. Putin was pictured lecturing his defence chiefs, cowering at the other end of a 6-metre long table. But not long afterwards, the same officials were shown sitting at his side. The long table turned out to be theatrics – Putin’s version of Nixon’s “madman” theory, to make him appear so irrational that anything was possible, even nuclear war.

'Then western officials argued that Putin was terrified at the prospect of a democratic Ukraine on Russia’s border, which would threaten the basis of his power by showing Russians that they too could live differently. On the face of it, that seemed plausible. Putin hated the “colour revolutions” that, from 2003 onwards, brought regime change to former Soviet bloc states. But Ukraine’s attractions as a model are limited. It is deeply corrupt, the rule of law is nonexistent and its billionaire oligarchs wield disproportionate power. Should that change, the Russian intelligentsia may take note but the majority of Russians – those fed on state propaganda who make up Putin’s political base – would not give two hoots.

'The invasion has also been portrayed as a straightforward imperialist land grab. A passing reference to Peter the Great earlier in the summer was taken as confirmation that Putin wanted to restore the Russian empire or, failing that, the USSR. Otherwise sensible people, mainly in eastern Europe but not only, held that Ukraine was just a first step. “I wouldn’t be surprised,” a former Swedish minister told me last week, “if, in a few years, Estonia and Latvia are next in line.”

'Given that Putin once called the collapse of the Soviet Union “the greatest geopolitical catastrophe of the 20th century”, that may seem to make sense. But he also said: “Anyone who does not regret [its] destruction has no heart; anyone who wants to see it recreated has no brain.” Leaving aside the fact that the Russian military is already hard-pressed to achieve even modest successes in Ukraine, an attack on the Baltic states or Poland would bring them into direct conflict with Nato, which is the last thing that Moscow (or the west) wants.

'In fact, Putin’s invasion is being driven by other considerations.

'He has been fixated on Ukraine since long before he came to power. As early as 1994, when he was the deputy mayor of St Petersburg, he expressed outrage that Crimea had been joined to Ukraine. “Russia won Crimea from the Turks!” he told a French diplomat that year, referring to Russia’s defeat of the Ottoman empire in the 18th century.

'But it was the possibility, raised at a Nato summit in 2008, that Ukraine should become a fully-fledged member of the western alliance that turned his attitude toxic.

'Bill Burns, now the head of the CIA, who was then the US ambassador to Moscow, wrote at the time in a secret cable to the White House: “Ukrainian entry into Nato is the brightest of all red lines for the Russian elite (not just Putin). In my more than two-and-a-half years of conversations with key Russian players, from knuckle-draggers in the dark recesses of the Kremlin to Putin’s sharpest liberal critics, I have yet to find anyone who views Ukraine in Nato as anything other than a direct challenge to Russia’s interests … Today’s Russia will respond.”'