For a century or more the ALP harboured many brands of left-wing views.
Anyone who didn't fit into the 'broad church' of ALP politics (eg communists and trots) basically gained no traction at all at the ballot box (with the honourable exception of Fred Patterson in Queensland).
For that reason the ALP has never before experienced a serious electoral challenge from its left flank.
The Greens won't replace Labor as Bob Brown hopes, but they will seriously damage the ALP's electoral prospects for sometime to come.
Without, a credible left-wing competitor, the ALP's national primary vote mostly held up well over 40 per cent even through the periodic splits and other dramas of the twentieth century.
The LNP coalition can still look forward to a primary vote in the mid to high forties, but those days are long gone for the ALP.
During the Hawke / Keating era, many voters believed that the ALP had become a centrist, neoliberal party with a residual commitment to social justice ie more like the Libs than the ALP of Whitlam, Chifley and Curtin.
There's a lot of mythology around all that but that's the way lots of people saw it.
In a post cold war world, the ALP was moving away from the left-wing component of its base without replacing it with anything.
Moving to the centre seemed to come without much of an electoral price. The ALP could pick up some swinging middle class voters without much downside.
Several generations of ALP strategists saw that this was pretty clever because the left had nowhere else to go. So stuff them.
Then in the 80s and 90s a new type of left emerged in the form of the Greens, people with some old-time ALP left socialist views (implaccable opposition to private education and privatisation, and unwavering support for the centralised wage fixing system) and a new middle class fetish for the environment (ie trees before jobs).
Those ALP strategists were delighted. Greens preferences helped the ALP win the 1990 election by winning over some middle class Libs and swinging voters worried about the environment and by giving the disillusioned lefties a credible reason to keep voting ALP.
The ALP's clever strategists also used issues like uranium mining to help drive the exodus of left-wing branch activists from the ALP to the Greens, helping to shore up their position in pre-selections and to ensure that a party controlled by blue-collar unions did not go too far down the path of prioritising trees over jobs.
The Greens direct about 90 per cent of their preferences to the ALP anyway so why care, the ALP, they thought, could be pro-development, pro jobs, socially conservative and pick up the 10 to 20 per cent of voters attracted to the Greens through Australia's handy compulsory preferential system.
A damn lot easier than reforming the ALP and making sure it is relevant in a post blue collar post-corporatist society.
Clever strategies have a way of getting out of hand.
The ALP will be lucky to get over 40 per cent of the primary vote anytime soon.
The ALP's branch structure is collapsing, even faster than union membership as a proportion of the workforce.
The collapsing branch structure has further centralised control of the ALP with some union heavies and a few senior MPs. Further exacerbating its organisational and structural problems.
The ALP has never been able to reconcile its reliance on inner city lefties with its attempts to woo aspirational outer suburban Howard battlers back off the Liberals. The more the public sees the ALP trying to sit astride two stools the worse it is for the party's image.
Now the tail is starting to wag the dog.
The ALP looks like it is a coalition partner with the Greens, with disastrous results in the polls both federally and in Tasmania.
For years the ALP smarites saw a vote for the Greens as a vote for the ALP, now a lot of voters are seeing a vote for the ALP as a vote for the Greens.
Yesterday's shenanigans won't change that.