Christine Milne has resigned, and it’s breathtaking how little anybody seems to care. You can’t help but compare her departure to the one we gave Bob Brown; the jubilation of his foes, the weeping and gnashing of teeth by his supporters.

Even though most of them would never have voted for him, Australians quite liked Bob Brown. We liked his humour, his distaste for authority, his ill fitting suits. Even when he was propagating economically and morally insane ideas – advocacy of global government springs to mind – he usually managed to say it in a rather charming way. For many Australians, Bob Brown was the Greens. Without him, Piers Akerman augured the party was ‘beginning to slide’, Andrew Bolt predicted the Greens had ‘nowhere to go but down’, and the Herald Sun editorialised ’GREENS HEADED FOR SLOW DECLINE’.

Milne’s departure has not inspired that sort of passion from anybody. The warmest credit that Di Natale, her replacement, could think of in his political obituary for her was that she was chummy with the ‘colossus’ Bob Brown. In hindsight, we can say that everybody who predicted that Milne would be a weak leader has now been proven right.

And yet under her stewardship the Greens refused to shrivel up and die. With Milne at the helm their popularity, if anything, grew. Earlier this year in Queensland they won the highest percent of the vote they’d ever managed in that state. They did even better in NSW, winning three lower house seats seats, almost four, in their best result ever in mainland Australia. The Greens are now within striking distance of taking lower house federal seats away from high profile Labor leaders like Tanya Plibersek and Anthony Albanese.

Christine Milne, as grating as she was, did not hurt her party’s fortunes one jot. The deciding factor, rather than personality, is that the policies of the Greens are single-mindedly focused on appealing to white, middle-class, inner-city atheists, who continue to flock to the party.

I’m the sort of bourgeois, God-fearing chap who believes that if the Greens were actually able to win and wield executive power, the result would be disastrous: the price of doing business would skyrocket, as would the cost of living, the GDP would shrivel, our freedoms would be obliterated, etc. And yet I, and many Australians, find the enthusiasm that the Greens have for their terrible ideas absolutely refreshing. In the lead up to an election, the major political parties release as few policies as they can in a desperate attempt to alienate as few of their traditional voters as possible. The Greens, however, not only release, but cost all of their policies, and disseminate the information with absolute candour. It’s catnip for people who don’t know better.

For years, the growth of the Greens was stymied by their being perceived as a ‘party of protest’ that couldn’t actually get anything done. Vast swathes of voters whose views more closely aligned with the Greens would nevertheless vote ALP. This has begun to change now that the Greens have ruled federally with Labor.

It was again wrongly predicted by many that a Labor-Greens entente was going to expose the Greens as being incapable of wielding executive power. The opposite occurred; coalition government showed that the Greens were disciplined, more so than Labor, and that they were entirely capable of manifesting their policies in legislation. Again, bad legislation quickly overturned by Abbott, but legislated nevertheless.

You can make the case that, historically, minority governments end up strengthening the party that is further away from the centre of politics. After joining up with the Tories we have seen the the centrist Lib-Dems implode. It would be, perhaps, too cheeky to compare the Greens to the National Socialists in 1933, but I think we’re on relatively solid ground to draw a parallel with the first Labour Government in the UK in 1924, which needed the support of Asquith’s Liberals to rule. Power has helped to legitimise the Greens, at the expense of the ALP. The result? We may be witnessing the biggest existential crisis in progressive politics in a generation.

A substantial portion of the ALP has thrice split away from the party. On each occasion, the result has been severely detrimental to the electoral prospects of those left of centre. In 1916 the party split over conscription, and did not return to power for thirteen years. In 1931 the party split again, this time over how to respond to the Great Depressionand was in opposition for a decade. The most painful division came in 1955; the ALP-DLP Split led to 23 years of dominance by the coalition.

Although the ALP itself hasn’t split, its voter base has, which really amounts to much the same thing. Labor has traditionally had two key constituencies: blue-collar workers and white-collar progressives. A tremendous divide separates these groups on countless hot potato issues. The white-collar wing are happy to extend welfare, while the blue-collar wing resent ‘dole bludgers’. The white-collar wing want action on climate change, the blue-collar wing don’t want a rise in the cost of living. The progressives want gay marriage and open borders and the workers, for the most part, don’t. Every one of these issues is poisonous to Labor. Caught in the centre, they can only haemorrhage votes to the Liberals or the Greens.

The Greens are uniquely appealing to the progressives because, unlike Labor, they only want enough of the vote as would afford them the opportunity to rule in coalition. They can be unabashedly true to their one homogenous constituency. It’s compelling stuff, and it’s only going to get more compelling now that Di Natale – who very nearly seems like a real human being – is the new leader.

Labor is doing lots of soul searching at the moment as to whether it should remain fastened to the unions or break away and become a feel-good social-democratic party that still appeals to the workers for votes. It is a choice that has already been made for them. The feel-good mob are already departing for the Greens. Labor shouldn’t bother about how to avoid a split; it has already happened.