SINCE my days at university, I have supported police who are confronted by radical students and their somewhat older cohort of revolutionaries, who present themselves as modern-day followers of Leon Trotsky.

The Bolshevik Trotsky murdered Russian sailors at Kronstadt in 1921. And today’s Trots seem to delight in attacking police, who tend to comprise the remnants of what was once called the working class.

The scene in Melbourne last Wednesday of a demonstrator punching a young policeman in the back of the head indicated the contempt some radicals have for those employed to uphold law and order — and freedom — within democratic societies.

The recent violent demonstrations against Foreign Affairs Minister Julie Bishop at the University of Sydney and former Liberal MP Sophie Mirabella at the University of Melbourne demonstrate the authoritarian intolerance of the contemporary radical Left.

Those who comprise groups such as the Socialist Alliance and the Education Action Collective do not want to engage in discussion. Rather, they want to close down debate.

This is part of the authoritarian mindset that is prevalent within the extreme Left and the extreme Right. In Western societies, the totalitarian Right collapsed following the military defeat of Nazism and fascism. The totalitarian Left, however, has not completely gone away. Moreover, some of its heroes — such as Vladimir Lenin, Mao Zedong and Ho Chi Minh — have not been discredited in left-wing thought.

Most of the contemporary campus Left has probably never heard of German-born Marxist Herbert Marcuse (1898-1979) who was much admired by the Left intelligentsia half a century ago. It is often a sign of important thinkers that their influence extends through the ages in an anonymous manner.

In 1965, Marcuse published his essay Repressive Tolerance. Marcuse advocated what he termed “liberating tolerance”. This entailed “intolerance against movements from the Right and toleration of movements from the Left”. Marcuse advocated “the withdrawal of tolerance from regressive movements”; that is, org­anisations with which he dis­agreed. And Marcuse proclaimed the need for the Left to exhibit “intolerance towards the self-styled conservatives, to the political Right”.

On the advice of the Australian Federal Police, Tony Abbott cancelled a visit he and Education Minister Christopher Pyne were to make to Deakin University in Victoria on Wednesday.

That morning Rowan Payne, from the Deakin University Student Association and the National Union of Students, appeared on ABC1’s News Breakfast program. Payne was given numerous opportunities by presenter Virginia Trioli to condemn the intolerance exhibited against Bishop and Mirabella along with the threat of violence that had prevented the Prime Minister from visiting Deakin University.

Payne said that he and his fellow students were “terribly upset” with the Abbott government and looked back in happiness to “the glory days of free education in this country”.

Free tertiary education was introduced by Gough Whitlam’s big spending, big taxing Labor government in the early 1970s and abandoned by Labor prime minister Bob Hawke just over a decade later. Hawke did not see any glory in the fact men and women in the police force and elsewhere were compelled to fund the tertiary education of students who were destined to earn much more than they did.

As was the case with student radicals in the 60s and 70s, Payne and his fellow intolerant comrades get succour from their teachers. On the day that Abbott’s visit to Deakin University was cancelled, Scott Burchill appeared on News Breakfast. Burchill is a left-wing academic at Deakin University who has spent most of his career in taxpayer funded or subsidised employment.

To the apparent surprise of Trioli and her co-presenter Michael Rowland, Burchill essentially endorsed the action against Bishop and Mirabella. He maintained that: “When you start hacking and cutting and taking away people’s budgets and forcing them to work longer hours or study longer, you shouldn’t be surprised that people get angry and upset about these things.” Burchill went on to rationalise physical attacks as “the traditional university way”.

Right now, Marcuse’s concept of repressive tolerance seems all the rage within Western universities. In recent times, the supposedly left-liberal Brandeis University in the US overturned its decision to grant heroic Somali-born human rights activist Ayaan Hirsi Ali an honorary degree. What’s more, former US secretary of state Condoleezza Rice felt forced to withdraw from giving the commencement address at Rutgers University.

Hirsi Ali was attacked by left activists for her forceful opposition to Islamism in general and female genital mutilation in particular. Rice was condemned for the fact she supported the coalition of the willing’s invasion of Iraq to remove the dictator Saddam Hussein. There is a widespread view on many campuses that what the Left depicts as “error” has no right to exist and that those “in error” have no right to enter universities.

To some extent, this intolerance is encouraged by the fact so much of what passes for debate at contemporary universities and literary festivals is a left-wing stack.

Take the University of Melbourne, for example. Its public lectures for May contained a segment entitled “Budget assessment”. There was only one view heard: that of University of Queensland left-wing economist John Quiggin.

In 2012 its law school’s Wednesday Lectures series featured only left-wing speakers, namely Raimond Gaita, Larissa Behrendt, Gerry Simpson and Robert Manne. It was much the same last year.

When institutions such as this sponsor forums where all speakers agree with each other in a leftist kind of way, it’s hardly surprising when the radical Left physically attempts to prevent conservative views from being heard on ­campus.