Australia’s new sedition laws, enacted amid much controversy at the end of 2005, make it a crime to urge “a group or groups (whether distinguished by race, religion, nationality or political opinion) to use force or violence against another group or other groups (as so distinguished)”.

That should be enough to catch not just Alan Jones, but also Sheikh Feiz Mohammed, who was the centre of controversy at the weekend over a DVD series in which he allegedly encourages Muslim children to become martyrs and refers to Jews as “pigs”. (Note: I haven’t seen the video, so I can’t say whether the media’s account of its contents is correct — experience counsels scepticism in such things.)

But Attorney-General Philip Ruddock has always wanted more than just the sedition law: he wants the film and literature classification laws upgraded to outlaw this sort of material. In other words, he wants to be able to ban unpleasant opinions before they reach the public.

This has always been the acid test of free speech: not whether speech can be penalised after the fact for breaking various laws, but whether it can get into the marketplace of ideas in the first place. Laws on sedition, blasphemy, defamation and so forth can chill free speech, but prior restraint is the real killer.

Two quite different things are going on with the Feiz Mohammed videos. On the one hand, there is a classification system supposed to guide viewers on what to expect; an information function rather than censorship. It’s understandable that people would be surprised to find the sheikh’s sermons given just a “PG” rating, the second lowest (after “G”).

But that just shows the current classifications are muddled — which we knew anyway, from the radically different treatment given to explicit sex (banned, except in the territories) and explicit violence (let through with MA or, at worst, R ratings).

The classification system, however, is also a censorship regime, which prevents Australians from seeing or reading material of their choice, even in the privacy of their own homes. Any extension of that regime should be viewed with the greatest alarm.