This tale of two revolutions and two anniversaries may yet have a twist

During the Velvet revolution of 1989 I spied an improvised poster in a Prague shop window. It showed "68" spun through 180 degrees to make "89", with arrows indicating the rotation. Nineteen sixty-eight and 1989: a tale of two revolutions. Or at least, two waves of what many called revolution at the time. A 40th anniversary this year, a 20th next. Which of the two will be most memorialised? And which actually changed more?

Nineteen sixty-eight will be hard to beat in the commemoration stakes. Already, more ink has flowed recalling that year than did blood from the guillotines of Paris after 1789. Reportedly more than 100 books have been published in France alone about the revolutionary theatre of May 68. Germany has had its own beer-fest of the intellectuals; Warsaw and Prague have revisited the bitter-sweet ambiguities of their respective springs; even Britain has managed a retrospective issue of Prospect magazine.

The causes of this publicistic orgy are not hard to find. The 68ers are a uniquely well-defined generation all across Europe - probably the best defined since what one might call the 39ers, those shaped for life by their youthful experience of the second world war. Having been students in 1968, they now - at or around the age of 60 - occupy the commanding heights of cultural production in most European countries. Think they're going to pass up a chance to talk about their youth? You must be joking. Not important, moi?

There is no comparable class of 89. The protagonists in that year of wonders were more diverse: seasoned dissidents, apparatchiks, church leaders, middle-aged working men and women standing patiently on the streets, finally insisting that enough was enough. Students played a role in a few places and, 20 years on, some of them are now prominent in their countries' public lives. But the leaders of 89 were generally older, and many of them were, in fact, 68ers. Even the Soviet "heroes of retreat" around Mikhail Gorbachev were shaped by memories of 1968.

It's a general rule that the events we recall most intensely are those we experienced when young. The dawn you glimpsed when you were 20 may turn out to have been a false dawn; the one you witness at 50 may change the world for ever. But memory, that artful shyster, will always privilege the first. Moreover, while 1968 happened in both the western and the eastern halves of Europe, in Paris and in Prague, 1989 only really happened in the eastern half.

Politically, 89 changed far more. The Warsaw and Prague springs of 1968 ended in defeat; the Paris, Rome and Berlin springs ended in partial restorations, or only incremental change. Probably the largest street demo in Paris, on May 30 1968, was a manifestation of the political right, which the French electorate then returned to power for another decade. In West Germany, some of the spirit of May 30 flowed more successfully into Willy Brandt's reformist social democracy. Everywhere in the west, capitalism survived, reformed itself, and prospered. The events of 1989, by contrast, ended communism in Europe, the Soviet empire, the division of Germany, and an ideological and geopolitical struggle - the cold war - that had shaped world politics for half a century. It was, in its geopolitical results, as big as 1945 or 1914. By comparison, 68 was a molehill.

Revisited today, much of the Marxist, Trotskyite, Maoist or anarcho-liberationist rhetoric of 68 does look ridiculous, childish and morally irresponsible. It was, to quote George Orwell, a kind of playing with fire by people who don't even know that fire is hot. Evoking the beginning of a "cultural-revolutionary transitional period" - Chairman Mao's brutal cultural revolution thus being held up as a model for emulation in Europe - and describing the Vietcong as "revolutionary forces of liberation" against US imperialism, Rudi Dutschke told the Vietnam congress in West Berlin that these liberating truths had been discovered through "the specific relationship of production of the student producers". The production of bullshit, that is. At the London School of Economics they chanted: "What do we want? Everything. When do we want it? Now." Narcissus with a red flag.

Those who in 1968 were so harsh on the way some of their parents' generation (the 39ers) had been fellow-travellers with the terrors of fascism and Stalinism might wish, on this anniversary, to make a small reckoning of conscience about their own lighthearted fellow-travelling with terror in faraway countries of which they knew little. But many leading representatives of the 68 generation went on to learn from these mistakes and frivolities. They engaged over subsequent decades in a more serious politics of liberal, social democratic or green "new evolutionism" (to borrow a phrase from the Polish 68er Adam Michnik), including the ending of a slew of European authoritarian regimes, from Portugal to Poland, and the promotion of human rights and democracy in far-away countries of which they learned to know more.

A balance sheet that describes 68 only as frivolous, evanescent and non-consequential, by contrast with a serious and consequential 89, is thus too simplistic. An essential point is made by that archetypical 68er Daniel Cohn-Bendit: "We have won culturally and socially while, fortunately, losing politically." Nineteen eighty-nine produced, with an astonishing lack of violence, a transformation of structures of domestic and international politics and economics. Culturally and socially, it has more the character of a restoration, or at least the reproduction or imitation, of existing western consumer societies. Nineteen sixty-eight produced no comparable transformation of political and economic structures, but it did catalyse a profound cultural and social change, in eastern as well as western Europe ("1968" here really stands for a larger phenomenon, "the 60s", with the spread of the pill being more important than any demos or barricades).

No change of this scale is ever only for the better, and we see some negative effects today; but on balance, this was a step forward for human emancipation. In most of our societies, most of the time, the life chances of women, of people from many sorts of minority and from social classes previously held back by stuffy hierarchies, are much greater today than they were before 1968. Even critics of 68 such as Nicolas Sarkozy are beneficiaries of this change. (Could the divorced son of migrants have become president in the pre-1968 conservative idyll of his imagining?)

Sharply contrasting though the two movements were, it is the combined effect of the utopian 68 and the anti-utopian 89 which has produced, across most of Europe and much of the world, a socially and culturally liberal, politically social democratic, globalised version of reformed capitalism. Yet in this anniversary year of 68, we are seeing trouble in the engine-room of that reformed capitalism. What if the trouble gets worse next year, just in time for the anniversary of 89? Now, that could be a revolution.

Timothy Garton Ash