The man who set out to revitalise the flagging Soviet Union ended up leading it headlong to destruction

There's been plenty of time to reflect on what went wrong - from the euphoric early days of perestroika to crisis and collapse. His memoirs - published in 1995 - are, among other things, an effort to distribute blame.

Historians have been doing the same, picking over the Gorbachev era with a fine-tooth comb, exhaustively and sometimes gleefully cataloguing the mistakes of the last Soviet leader, from his failure to submit to democratic election, to his obstinate refusal to heed repeated warnings of the threat from the hardline communist right.

Paradoxical legacy

Most find themselves pondering over a central irony, that the man who set out to revitalise the flagging Soviet Union ended up leading it headlong to destruction.

Gorbachev did not like or respect his successor Boris Yeltsin

The leading Russian historian of the 1990s, Dmitri Volkogonov, uses the word "paradox" more than any other in his account of Gorbachev in power - the convinced Communist who killed Communism; the Leninist who believed Soviet power could be democratised; the utopian - hailed in the West but reviled at home - who unwittingly opened the sluicegates that washed away the USSR.

His fatal flaw seems to have been the belief that he could start a revolution and that the Soviet state would be able to prevent it running out of control.

At the same time, he underestimated the latent force of nationalism in the Soviet republics, and the extent to which the truth about the USSR's bloody history would undermine its legitimacy in the eyes of its own citizens.

In retrospect it's clear that Gorbachev would have been wise to think twice about bringing Soviet totalitarianism to such an abrupt end - though this is the achievement for which he will be remembered more than any other.

The wider context

At the same time, he was not alone in failing to grasp the strength of the centrifugal forces building in the USSR.

The Soviet people wanted access to Western goods

For example, as late as summer 1991, then US President George Bush was pointlessly urging Ukrainians not to quit the Soviet Union, in a notorious speech now dubbed the "Kiev Turkey".

Up to now historians have focused attention on Gorbachev's strategy and his tactics - his hesitation, his futile search for consensus, his failure to join forces with other reformers.

Less has been written about the context in which he was acting - a longstanding process of Soviet decline, in which he was just one of many players, though by far the most interesting.

Gorbachev hastened the decline of the Soviet Union, but it was in serious trouble before he came on the scene, and maybe no-one could have saved it.

From this perspective, it is of key importance that the Soviet Union was in steep economic decline even before Gorbachev took the reins of power. This was a key factor that conditioned the Soviet withdrawal from Eastern Europe and from Afghanistan, and its decision to halt the arms race.

Already aware of the superiority of Western, or even Eastern European, consumer goods, the growing public knowledge in the USSR that the economic race with capitalism was being lost had already begun to undermine belief in the Soviet system itself.

National consciousness

With growing local elites to sustain it, national consciousness in the republics had been strengthening before Gorbachev came to power.

Stalin's influence had faded by the 1980s

The historical inquest into Stalinist repression had also been opened almost immediately after the tyrant's death, in the 1950s.

Although it was quickly closed again, the mere passage of time had a relaxing effect. As the memory of terror receded, Gorbachev's generation was already less cowed than its predecessors.

Gorbachev hastened the decline of the Soviet Union, but it was in serious trouble before he came on the scene, and maybe no-one could have saved it.