Is Bob Brown a Nazi?

A couple of years ago, Liberal Senator George Brandis made a right dickhead of himself on Lateline trying to defend his thesis that Bob Brown and the Greens "are Nazis influenced by Nazism."

Now that SB has resurrected the "Leftists are Nazis" and "Leftists are anti-Semitic" memes in previous comment threads, I'd like to know what others think.

My own take is that contemporary leftism is by and large libertarian leftism, and is an outgrowth of both the social democracy that flourished in the post-war period (including the New Deal and the rise of the welfare state), and the so-called "New Left" discourses that emerged in the Sixties. Contemporary leftists advocate an economy and a polity that is based upon fairness and the principle of "equality of opportunity"--a principle all but abandoned by many on the right as they have become more and more authoritarian in their outlook, particularly after Sept. 11. (Another trend we notice is that those on the authoritarian left and the libertarian right are increasingly marginalised in conventional politics.) What this means, I submit, is that the majority of those on the left--being libertarian leftists--couldn't be further removed from Nazism, which is based on the fundamental principle of inequality (which it counts as a virtue).

What's your take? Is leftism authoritarian by nature, as SB suggests? Or can one simultaneously be economically left-leaning and socially libertarian?