That's a claim it can rightly make, and comfortably so. No one would argue that.
The modern Labor Party however, is another story.
It's a micromanaged juggernaut of political spin and snobbery, with union heavy weights just always holding a mallet over the heads of those in the party whom are more progressively minded.
I cite Kevin Rudd as one example, who came from no factional base.
Following the saga of Labor MP Craig Thomson and the whole sorry sordid public affair that became, you would think Labor would just like to keep things peaceful for the time being and stay out of the press over this long winter break.
But, no, no, oh no - that's not good enough.
Yesterday, an article was published in the Daily Telegraph by Paul Howes backing calls by the well-connected Sam Dastyari of the NSW Right to preference the Greens last on Labor how-to-vote cards.
Here is the opening paragraph from that article:
There probably wouldn't even be a State of Origin - we'd just sit around with Queenslanders and play pass the parcel. After all, the Greens in NSW have a policy of promoting "non-competitive sports" such as yoga, dance, trampolining and tai chi over the traditional sports that Australian children enjoy playing.
He also goes on to suggest that there will be no football under the Greens. Is he implying that there is somehow some sort of veiled threat of the Greens taking full political power? Paul Howes may well be a great unionist leader, but he surely must know better by now not to shoot his loud bombastic mouth off left, right, and centre.
And this morning, Greg Combet, another former union heavy weight, backed Paul Howes:
"The Labor Party is a different political organisation with a long and proud history," he told the ABC.
"We've been enormously important in the history of this country. The Greens are some other show, I'm not interested in them.
"I'm Labor and Labor will be distinguishing itself from the Greens, there's no doubt about that.
"To be honest I don't spend too much time thinking about the Greens, I've got a lot of work to do implementing important reforms."
The question I have to ask is, just why? Why begin this attack yet again on the Greens.
Gillard herself has done this before in a vain attempt to distance her party from the Greens, who the public perceive Labor as being in coalition with, and perhaps even dictated by.
True, this blog is all about 'reassessing the left' but we have to keep in mind that this all about power plays between one centre-left party (Labor) and one left party (Greens).
The problem with the centre-left is that they like to try to please everyone - even the far left Greens themselves by introducing a carbon price (tax) after explicitly stating there will be no carbon tax under a Labor government.
Of course Labor had to change its tune - they needed to negotiate with the Greens on the carbon tax, and Greg Combet now loudly and proudly heralds the carbon tax as being great policy at every given opportunity, as does every other Labor minister.
Paul Howes of course doesn't know where he stands. On one hand, he bashed the carbon tax and threatened to start World War III if even just one union member worker lost one job, but on the other hand, he's also backflipped and subsequently defended the tax as being fantastic Labor policy.
Well, strike me down and tickle me pink.
Before the election, there was going to be no carbon tax, but once they needed to negotiate and form minority government with the Greens, it was suddenly a good idea.
However, I'm not commenting on whether or not the carbon tax is good policy; there's plenty of people better informed to do that.
My personal opinion though is that it's more about a slippery and limp-wristed attempt at economic reform than any type of environmental reform.
And heck, even the biggest selling point is that students and pensioners get a token lump-sum payment to 'compensate' for a tax. If the whole point of a carbon tax is to set up price signals, what's the point of the tax if there is 'compensation' - compensation usually means a wrong has been done.
They don't even know yet what the floor price will be for one ton of carbon, barely a week into the tax.
However now that the carbon tax has been implemented, Labor has let loose the attack dogs on the Greens in a desperate attempt to try and separate themselves from what they see as a liability, a gangrenous limb that needs to be loped off post-haste.
'We're different, we're a different act,' is the loud and proud catch-cry now, trying ever-so-desperately and snidely to make it known that they don't share the same 'values' of the Greens.
A very public lovers' tiff is not the way to do that, and it's extraordinary if not even pathetic to watch.
The problem is, according the Paul Howes, the only values that matter in this country are working class dinky-die slap-ya-mates-on-the-bum values, which he and others of the Labor ilk are not ready to admit is not universal law in Australia.
There's a range of values. From the poor, homeless, and unemployed, to big business interests.
It may also be damaging to Paul Howes' sense of sexuality that the Greens are lobbying for gay marriage in this country - which must be why he opened his article with boofhead speak of there being no football, and painting the Greens as soft pansies.
Is gay marriage one of the 'extremist' policies that scares he and Labor union heavies?
Well I'm not sure.
I have already written about gay marriage and how it is not perhaps the most pressing issue in Australia, even though the left, such as the Greens, enjoy harnessing great political capital from it.
But you could hardly call gay marriage an extremist leftist policy.
It's more of progressive policy, that truth be told, will most likely in the future be a normalised and accepted tradition in Australia.
Paul Howes also took a swing at the Greens for wanting to decriminalise 'hard' drugs while still being against cigarettes and alcohol.
If you look at the numbers, the damage and national health costs of booze and smokes quite simply dwarfs that of 'hard' drugs - and it's an obvious fact that the 'war on drugs' has been a policy failure.
So I can't exactly see anything 'extremist' there, but more or less a new way of looking at the problem of social decay that drugs can cause.
Of course, booze and smokes are for Paul Howes' downtrodden working classes, so there's nothing wrong with them.
The very crux of this is that Labor has lost its spot as Australia's progressive political party. They have no new ideas, they have no new bold overarching narrative, and they have no new big and gleaming light on the hill now to aim for.
They are, for all intents and purposes, disappearing into political irrelevancy.
A look at Queensland Labor demonstrates this.
Following the last recent state election, they now only command 7 seats - a piffling number, and they barely exist as a party in that state after previously commanding 51 seats.
Surely this must send warning signals to Labor at the federal level that they are in a deep crisis. Nation-wide, Labor has been losing state elections while flailing for a reason - of course they try to differentiate the cancer from federal Labor, but the message is clearly there that the ship is sinking.
Labor membership numbers have also been dropping like flies at a dinky-die Aussie barbie in bug zappers.
Labor have nothing to sell. They may all well be great salesmen, I mean look how they sold the carbon tax - but that was a Greens policy, and yet they somehow think they can claim relevancy again by trashing and destroying any rival minor political party.
It's yet another very sad and unhealthy sign of Australia's democracy where we now have a major, yet disease-ridden Labor Party publicly stating through its faceless union overlords that it wishes to abolish the Greens.
It may well backfire on them in spectacular fashion.