Party elder John Faulkner's speech called for an engagement in politics, and the politicians sure engaged.

They stand at opposite ends of the ideological spectrum, but John Faulkner and John Hewson have come to the same conclusion about the biggest structural question of Australian politics today.

That question is the future of the progressive vote in Australia. Labor used to have it, or at least enough of it to hold power. But it lost its critical mass of progressive voters to the Greens in 2010.

In three weeks, when the new senators take their places, the Greens will have 10 parliamentarians in the two chambers of the Federal Parliament: Adam Bandt in the House of Representatives and nine in the Senate.

This is more than the nine the Democrats had at their peak, more than any third party has had in postwar Australia. The Greens will have one of the four balance-of-power votes in the House and they will hold the balance of power in their own right in the Senate.

In the past 48 hours Faulkner, a hero of the Labor Left, and Hewson, a Liberal ultra-dry, have each delivered their considered opinions. They concur that this is a great moment for the progressive vote. It's just that Faulkner sees it as a deadly danger, while Hewson sees it as a great opportunity.

The extraordinary thing is that both men managed to get through the subject without once uttering the name of the party that is, at the moment, the repository of the progressive vote: the Greens.

The former Liberal leader's column in The Financial Review yesterday, headed "Time for a third force," opened by observing: "The most discernible trend in Australian politics over the past several decades has been the substantial narrowing of the differences between the major political parties, within a most significant drift to the 'right'.

"In previous times, the 'left' of both major parties would have been much more active, vocal and politically influential. With a hung parliament, the opportunity for them to be heard and influential has never been better. It was understandably more difficult under Keating and Howard, who simply dominated their respective parties. But now, when both Gillard and Abbott desperately need to keep their teams unified, the left has a unique opportunity to exert their positions."

Hewson went on to say: "I would suggest the time has never been better for a 'social democratic' force to emerge in Australian politics." He didn't seem to notice that it already has.

When I told a senior figure in the Greens yesterday of Hewson's view, he asked whether Hewson proposed a platform for this new force consisting of three major planks: action on climate change, withdrawal from Afghanistan and greater compassion for asylum seekers.

The answer is yes. That is exactly what Hewson suggests. It just so happens that it's the platform of the existing social democratic force, the Greens. My Greens interlocutor was incredulous.

Of course, for the Liberal Party, the emergence of such a party is excellent news, because it splits the Labor vote.

Labor has long been a two-legged electoral beast - the working class, outer-suburban "battler" vote on the one side and educated, inner-city progressive on the other.

Rudd Labor brought the two together in sufficient numbers to win in 2007. But beginning the moment Rudd deferred the climate change challenge, Labor ripped off its progressive leg and, in effect, handed it to the Greens.

It was the Labor leg that allowed the Greens to increase their vote by half, to a record 12 per cent of the primary vote, and put their foot in the door of the House of Representatives.

As a result, Labor failed to win re-election in its own right and needed to cobble together a coalition with the Greens and independents.

Labor has not recovered. Indeed, Labor's situation has only grown worse since the 2010 election, on the evidence of the polls.

Labor is now in an existential crisis. For the first time, it has a serious political challenger capable of taking seats from its left, as well as the traditional enemy on the right, the Coalition.

If an elector wants to vote for a conservative party, she can vote for a real conservative party, the Liberals. If an elector wants to vote for a progressive party, he can vote for a real progressive party, the Greens.

Why vote for the one in the middle? Only 31 per cent of voters would bother, according to the latest Herald Nielsen poll, and that's about 9 percentage points fewer than Labor needs if it hopes to stand for election as a party capable of governing in its own right.

This is exactly why Faulkner issued the most dire warning of his long political career on Thursday night. The former Labor president told an audience of party stalwarts: "The ALP has recently returned some of the worst election results in its history. And we have a long history." Indeed, it's 120 years long.

"We have, at a state and a federal level, looked at our dropping support - and more often than not, we have blamed the leader. And, in NSW, more often than not, we have changed the leader. It is time for the party to realise that there is more amiss here than any one individual can be asked to shoulder the blame for."

This point is important. Because Faulkner is both defending Kevin Rudd and protecting Julia Gillard. He is making plain that Labor needs structural change, not another change of leader.

And he is doing one other thing. By pointing out the inadequacy of changing leaders, he is also rejecting the Right faction, which has embraced changes of leader as a standard tool of political management.

Like Hewson, Faulkner did not name the Greens, but they were lurking just under the surface of his Neville Wran lecture at NSW Parliament House: "As party membership dwindles, ALP strategists talk about 'reaching out' to organisations active on particular progressive issues, 'gaining endorsement' of our policies," Faulkner said.

"That idea, with its implications of 'us' in Labor and 'them' in community organisations, is wrong. The frequency with which it's raised by hand-wringing apparatchiks makes many wonder if Labor has lost its way. Progressive, socially aware activists passionate about social and economic reform must never be outsiders to the Labor movement.''

In other words, Labor needs to bring the progressives back into the party. And that means bringing progressive policy and wider inclusion back into Labor, he argued. Then he came to the main target of his speech, Labor's Right faction, though, again, he didn't name it.

"I say to those who resist the opening up of our structures to more participation and more democracy because they see their control over managed and pre-negotiated outcomes slipping away - do not act like the ship's captain steering for an iceberg, refusing to turn over the wheel to a more competent navigator in determination to remain captain, even if only of a lifeboat."

Apart from being a NSW senator and co-author of the Labor internal review of the 2010 election, Faulkner is also a lifetime organiser and leading light in the party's Left faction.

When he spoke of the people who "resist the opening up," he meant the Right faction. The Right is dominant and is not interested in reviewing the structure of the party that it controls. "The resistance to reform by some within the ALP has made me very pessimistic about the possibility of achieving meaningful change."

Then Kevin Rudd joined the argument from Abu Dhabi by Twitter: "John Faulkner is spot on in his speech tonight. ALP members must be heard, not just permitted to speak."

This immediately did what Faulkner had been avoiding - turned it into an argument about the leadership. Rudd's critics in the caucus, and there are many, instantly seethed with anger and made the obvious rejoinder that Rudd, who ruled in splendid isolation, was hardly the man to talk about a more inclusive Labor Party.

Rudd followed up with interviews on ABC Radio where he escalated the confrontation. "This is the beginning of the reforms which are necessary and that's I believe the task which lies ahead at the national conference of the party at the end of this year ... The cancer within the ALP lies in factional power and lies in factional powerbrokers intimidating others from exercising their own free political will."

Where Faulkner was trying to be diplomatic in confronting the Right's death grip on the wheel of the ALP Titanic, Rudd effectively declared open factional warfare at the ALP national conference scheduled for December. He has now aligned himself publicly with the Left.

And where Faulkner was trying to transcend the bitter leadership resentments in Labor, Rudd has now turned the factional fight into a proxy struggle over the leadership.

It seems that Rudd agrees with Hewson and Faulkner that this is indeed a great moment for the progressive movement in Australia. Within Labor, he intends to be its champion.

So Labor is now arguing over whether it will try to recover the progressive vote. The Labor Right, content with its dominance of the party, isn't interested in trying.

The Labor Left hopes it will be enough to restore Labor to a position where it might again hope to win an election. And Rudd hopes it will be enough to restore him to the prime ministership.

labor peers into the abyss .....