Looking back through August 2008 eyes, many commentators now seem to treat the Warsaw Pact invasion of Czechoslovakia 40 years ago this week as a primarily geopolitical event. The coincidence of Russia’s invasion of Georgia and the anniversary of the invasion of 1968 perhaps makes it understandable that some should colour their thinking about the crushing of the Prague Spring this way. In this elision, securing their near-abroad against their empire’s enemies is what tsars in Moscow always do, whether the threat du jour is from American capitalists or Georgian nationalists. The common theme, in other words, is always Russian power politics.

Undeniably there are important and ominous connections here - and they are ominous not only to those who live in any country in that vast geographic Russian border arc that stretches south from Finland to the Black Sea and then east from the Caucasus towards Mongolia. No other state in the contemporary world treats its neighbours’ sovereignty with as much cynicism as Russia. Yet to concentrate on the geopolitics of enduring Russian insecurity is to downplay some of the other large historical lessons of what happened in August 1968 - and certainly to misrepresent what seemed to be most important about those events at the time. That is because the central question in the eight months between the appointment of Alexander Dubcek as first secretary of the Czechoslovak communist party at the start of Jan 1968 and the overnight arrival of 500,000 Soviet and Warsaw Pact troops on Aug 21 of that year was less geostrategic than political.

That question was big and it was simple. Could the Soviet communist model of socialism be reformed or not? Today we know the answer. But the world of 1968 could not be so sure. The question was at the heart of the Prague Spring. Dubcek’s reforms raised the possibility that there could be some kind of democratic socialist third way in which collective goals and socialist projects coexisted with democracy, free institutions and individual freedoms. Tony Judt is right to argue in his great book, Postwar, that the slogan of socialism with a human face was not just rhetorical and right to insist that the Prague 68ers didn’t “really” want to import liberal capitalism. They actually believed that reformed socialism could work.

As Zdenek Mlynar, a leading Czech reform Communist, later put it (as told by Judt), when Red Army troops burst in on a meeting of Dubcek’s politburo and lined up behind each member, the future of socialism was not the uppermost thought in most people’s minds. “But at the same time,” Mlynar went on, “you know that it has a direct connection of some sort with the automatic weapon pointing at your back.” August 21 1968 was not the day that communism died. But it was the day that communism’s death sentence was confirmed. Christopher Hitchens had a neat way of encapsulating the whole thing during a debate at the Hay literary festival earlier this year. If you flip 68 upside down, he said, you get 89. In eastern Europe the protest generation of 1968 was the generation who then replaced the Soviet system 21 years later. Dubcek himself, however, re-emerging in 1989 from long years of obscurity, was not part of it. Even in 1989 he remained wedded to the possibility of communist reform, even as communism was dissolving around him.

Yet August 1968 was also the beginning of a more general crisis for socialists of all kinds. Many in the western left in 1968 believed that Dubcek’s reform programme, though noble, was doomed. The Soviet invasion duly confirmed their view. Yet however firmly the western left dissociated itself from Soviet communism’s own crisis, many on the left remained wedded in various ways to the same ideological traditions of the French revolution.

Forty years on from the Russian tanks, the eclipse of socialism is now as general in the west as it is in the former Soviet lands further east. Most people who consider themselves to be on the left - whatever that really means in the post-1989 world - are aware at some level of this reality. Not enough of them, though, admit to it or what it implies for serious public politics. Even today, far too few of those who admit the reality seem to be prepared to think through what a credible, sellable, historically aware but modern progressive project that could really command sustained majority support in our post-socialist world should consist of.

Very few parties of the left have been equal to this task. In Britain in the 1990s, New Labour began to ask such questions, but not in a sustained way. Too many key, but hard, issues were ruled off the agenda. Yet the mere fact that New Labour attempted this task at all led to astonishing electoral dividends. Electoral success, however, meant that the political task was never carried through. After the Soviet invasion of Czechoslovakia the old political map was no longer usable. But the new map has yet to be drawn, let alone followed. - The Guardian