On the left, Marxism no longer sets the intellectual and moral compass as it did for 80 years. On the right, an older style of conservatism has been sidelined. This is symbolised by people like Malcolm Fraser and Robert Manne, whose conservatism was built on a moral outlook now disparaged by both amoral free-marketeers and neo-conservative populists who fan fears about cultural identity.

Like the anti-communism which Manne and Fraser once espoused, the ideas of Che Guevara and Mao Zedong are relics from a historical period now closed. But history still has its claims. One of them is an argument about interpretation.

The claim that Stalin and Hitler were equals is part of an argument which tries to prove that Marxism, as an intellectual framework, was akin to fascism.

Marxism, now largely defunct, was very unlike fascism. Marxism was very much part of the Enlightenment heritage of the West. It was an ideology based on rationalism, science and progress. As such it influenced social science and the humanities. Its critique of economic power has become part of the common sense of our era. It was the militant wing of the Enlightenment.

By contrast, fascism was a product of the counter-Enlightenment. Its call to blood, race and nation was utterly different to Marxism. Both produced dystopias but for different reasons. Marxism's fatal flaw was precisely its utopianism, based on a literal implementation of its Enlightenment values of equality and rationality. It took little account of the nature of human beings, and did not have a functional and elaborate moral sense. (A similar critique can be made of current ideologies of free-trade globalisation.)

That Marxism won a wide following in the West is therefore hardly surprising given that Marxism's core ideas were a utopian elaboration of core values of the modern West such as equality and fraternity. In Australia it is humorously, but probably accurately, said that the biggest political party has always been the ex-members of the Communist Party.

But is it true to say that Australian communists slavishly supported Stalin and leave it at that? Partial truths can distort as effectively as untruths.

It is true that until the late 1960s Australian communists believed that the Soviet Union was a progressive and humane society. They admired the opposition of the Red Army to Nazism during World War II. They denied the obvious truth that Stalin's rule rested on secret police, labour camps and an unworkable economy.

But history is paradoxical, not simple. While the Communist Party of Australia embraced a Russified Marxism and worshipped Stalin, it also represented a genuine extension of native Australian working-class radicalism. It was both a victim of the Cold War and it used Stalinist methods internally.

But it is also true that in 1968 the Australian communists were the first in the world to condemn the Russian invasion of Czechoslovakia. For the next 25 years, the Australian party chose an independent course, which included acknowledging the horrors of Stalinism.

One consequence of this independent period was the communists' embrace of environmentalism, which helped save much of Sydney's heritage from the demolisher's hammer. Another was that, alongside certain Christians, communists were some of the few Australians who could hold their heads high with a consistent record of opposition to racism against indigenous Australians.

Such stances won support from the young new-left radicals of the 1970s. I know because I was one of them.

I joined the Communist Party of Australia in 1972 at the age of 21 out of unashamed idealism but with a full awareness of the tragedy that was Stalinism. I was confident that socialism did not automatically lead to Stalinism. I had enjoyed George Orwell's Animal Farm and 1984 but also his idealistic Homage to Catalonia. Socialism and equality seemed so obviously the answer to the world's ills. By the late 1980s my views had changed. Both the problems and solutions were not so simple any more. I drifted out of the Communist Party and by 1991 the party itself dissolved.

Optimism, hope and idealism were associated with Marxism in a way that was impossible with fascism. The theory of fascism wanted to crush Jews, the disabled, trade unionists and many others. The theory of Marxism wanted a better world for all. In Nazi Germany fascist ideals were realised. In the Soviet Union, as in present-day Cuba, Marx's ideals were not realised, and can never be realised.

New kinds of idealism need to be rethought, not buried.