By the time a new leader is announced on Sept 15, it will be nine months since David Cunliffe put his grand ambition away in a box, having been sent to the Siberia of the backbenches for challenging David Shearer.
The time for the son of an Anglican preacher and a nurse may now have come. His unpopularity among some caucus colleagues, supposedly due to a distaste of his brand of ambition and a perceived smarminess, is said to be offset by his appeal to the party rank and file and a belief that the articulate and skilled debater is best able to take the fight to Prime Minister John Key.
Two sources who have worked closely with him are adamant he has what it takes to lead not just Labour but the country.
One, a health sector source, said he has the necessary character, brains and heart and was in politics "for all the right reasons" but had become a target because he was honest about his ambitions.
A former parliamentary staffer, who also spoke to the Herald for a profile of Cunliffe published in November, rated him an exceptional boss who was "warm, friendly, polite and caring about his staff".
He'd never seen him lose his temper with anyone despite long hours and the pressure of making tough political decisions such as approving animal organ transplants, sacking a hospital board, and going against the wishes of the strong Herceptin lobby.
He couldn't understand why Cunliffe attracted passionate opposition among some in caucus, including Shearer loyalist Clayton Cosgrove. "It is like there are two Cunliffes," he said. "The Cunliffe who was Cabinet minister dealing with stakeholders was liked and admired."
Cunliffe, 49, was a standout minister in Helen Clark's Government, succeeding, where others failed, in unbundling Telecom's local loop monopoly, and making bold decisions as health minister.
He has been described as the new wave of Labour's Third Way politicians: highly educated, wealthy and perhaps more comfortable in a boardroom than a workingmen's club. Not one for bar-room chumminess, he is said to excel more with women and kids than with other men.
Now in his 13th year in Parliament, he may be poised for the job he has marched towards from a young age. Born to a lower middle-class family, he rose courtesy of a quality state education. He met his wife, Karen, a lawyer, at Otago University and they have two sons.
His academic qualifications come attached with "honours" and "distinction" and are topped by a masters degree in public administration from Harvard, where he was also a Fulbright Scholar and Kennedy Memorial Fellow.
He has worked as a diplomat and as an economist and business strategist for the Boston Consulting Group which Mike Williams, party president during the Clark years, said initially gave rise to questions about his political position. But that background was an asset for a party that still lacks people with a business background. Williams said Cunliffe was a "brave" minister who was a good organiser and attracted good people.
The MP for New Lynn may choose to live in Herne Bay, where houses sell for $2 million, but his formative years were red. He was born in Te Aroha; his family moved to Te Kuiti and then to Pleasant Point, near Timaru, where the Rev Bill Cunliffe became active in the Labour Party.
A source close to the family suggests the father's Labour leanings rubbed off on a young Cunliffe, whom he described as sincere and proactive. He considered Cunliffe had fallen foul of tall poppy syndrome but conceded "there is ... a volume dial that could have been turned down in terms of his own sense of his ability".
Political columnist John Armstrong on David Cunliffe
"A big brain - and an even bigger ego to match. A huge talent which has frequently been suffocated by rampant ambition. Politically canny, imbued with the Labour ethos and a parliamentary debater with rare passion, Cunliffe could be a great leader. He could be a great disaster. No one can be sure which.
A former Cabinet minister, he has the requisite experience to do the job. In fact, he would already hold the job had he put in a good performance as finance spokesman during Phil Goff's tenure as leader. But he didn't. Goff felt undermined.
For some unfathomable reason, Cunliffe is currently the darling of the party's left faction. That may be enough to outweigh his unpopularity in the Labour caucus.
Has also kept his head down since his sacking from the front-bench following his destabilising of David Shearer at last year's Labour conference. He could give John Key a serious run for his money.
Those pluses may be enough to swing the leadership in his favour."
• Political editor Audrey Young on David Cunliffe
"Cunliffe has an uncanny knack of being both left-wing and right-wing, union-friendly and business-friendly, socially liberal and a devout Christian and family man, an urban latte-loving inhabitant of Herne Bay and an outdoorsy fisherman and tramper, a compassionate New Age guy and a tub-thumping mongrel campaigner. In short, all things to all people.
He has the potential to appeal to a broad cross-section of New Zealand, which sounds like an asset. But it is that chameleon-like quality that is also seen as a weakness. His greatest appeal is his ability to appeal, rather than being appealing for strongly identified qualities. He is seen as having more style than substance, and can easily slide into pomposity and theatrics.
He has a sound track record in Government as a capable minister. Crucially, he is good on television, and is a strong speaker.
The challenge for him would be to overcome the things that make him a magnet for mockery in sections of his own caucus as well as opponents. A surge in the polls under his leadership would do it."
Frequently touted as potentially New Zealand's first gay prime minister, Grant Robertson could also be the youngest in more than a century - barring, of course, David Lange, who helped to inspire him to pursue a career in politics in the first place.
At 41, Robertson is now the age Lange was when he became Prime Minister in 1984.
Should he succeed in the Labour leadership contest and reverse the party's fortunes over the following 14 months enough to win next year's election, he'd be 43 when he takes the top job - not as young as Lange but younger than Prime Minister John Key when he won the 2008 election.
Robertson has pointed to Lange's performance during the 1985 Oxford Union debate on nuclear weapons as a key influence, showing him not only that New Zealanders could foot it on an international stage, but also that "an overweight guy with glasses" could succeed.
That combination of self-deprecating humour and ambition is typical of Robertson.
Robertson was 13 at the time of the Oxford debate, and his drive to succeed and interest in politics were formed early.
Brought up middle class in Dunedin, Robertson - and his family - faced poverty and hardship after his father was jailed for two years for embezzling $120,000 from his employer.
He has cited the experience, including the insight into the failings of the justice system it gave him, as a key chapter in his political education.
But politics - and leadership - were themes throughout his education, including being head prefect at King's High School in Dunedin, and then president of Otago University Students' Association, where he gained a BA in political studies.
From there he was at the New Zealand University Students' Association in Wellington for two years before joining both the Labour Party and the Ministry of Foreign Affairs and Trade in 1997.
Initially working as an overseas aid officer for Samoa, he later took a job with the New Zealand team at the UN in New York.
His abilities were noticed back in Wellington and in 2001 he was hired by Labour as an adviser to Wellington Central MP and Cabinet minister Marian Hobbs.
After a year with Hobbs, he was moved across to Helen Clark's office where he stayed for four years, working closely with Clark and her famously formidable chief of staff, Heather Simpson.
Having been identified as a bright prospect to become an MP, he left Clark's office in 2006 and took Hobbs' Wellington Central seat in the 2008 election when she retired.
His rise through Labour's ranks has been swift and steady, and his handling of weighty portfolios including state services and health has been solid at the very least.
However, he's certainly no dry technocrat. While he doesn't possess the mercurial wit of his idol Lange, he is funny and quick on his feet in conversation and can foot it with John Key in Parliament.
He cultivates relationships with the media and has a finely tuned sense of how to work with them to press home attacks on the Government.
While there is likely to be soul-searching over whether New Zealand is ready for its first gay prime minister if Robertson becomes Labour leader, at least some of the potential angst will be defused by the fact that rugby and cricket-loving Robertson is, by his own description, pretty blokey.
He met Alf, his partner of the past 14 years, while playing rugby.
That blokey persona is subverted somewhat by the fact that he has little experience outside the public service and politics and still has something of the slightly earnest student politician about him, which is only underscored by his love of jangly Flying Nun guitar pop.
He has previously told the Herald he has faith that New Zealanders are more concerned with his ability than his sexuality.
"I hope that's what they'll judge me on."
John Armstrong on Grant Robertson
"Sensible, reasonable, personable, logical and approachable. Possesses nearly all the necessary attributes to be a highly competent leader.
Worked in the Prime Minister's office during Helen Clark's time there. Understands the ins and outs of political system intimately and the dynamics of the public service.
A former Foreign Affairs diplomat, Robertson was always careful not to overshadow Shearer. Has ability to distil complex messages in simple sound-bites. A creature of the liberal inner-city, he has yet to demonstrate he has the capacity to inspire more conservative Labourites. Also has yet to prove he can appeal to voters in the provinces where Labour was savaged in the last couple of elections.
Mad keen on sport and supporter of Ipswich Town Football Club. Gay, but not overtly so. Comes across instead as a Good Kiwi Bloke who likes a beer or two while chewing the political fat. That he is gay will not handicap him in the leadership contest, and equally might not handicap Labour if he becomes leader."
• Audrey Young on Grant Robertson
"Perhaps Labour's most natural performer in Parliament. That is a huge achievement for someone who has been an MP for just four and half years. And David Shearer's demise shows why the debating chamber is still important in politics.
Robertson is the classic political operator who knows his party inside out. As Heather Simpson's second-in-command in the Clark years, he knows how governments really operate.
He has had a dream run in politics, getting almost everything he wanted, including the deputy leadership after just three years.
Robertson has not been sullied by scandal or any failure of note but nor has he had any great political victories. His biggest was getting John Key to admit he had a childhood association with the GCSB director and a role in his appointment.
In Parliament, he is popular and is seen as having a collegial style of work there, but he has a low public profile. It is hard to see how the public would be inspired by him. But he might make a better fist of inspiring his Labour colleagues than David Cunliffe."
Other possible contenders for the Labour leadership
• Shane Jones - Sharp operator with sharp intelligence, but has promised more than he has actually delivered. Work ethic has been an issue with previous leaderships. Still handicapped by the "pornography in hotel room" scandal.
• Andrew Little - Has vast political experience as former high-profile trade unionist but still a comparative parliamentary novice. Good chance of becoming leader at some stage - just not this time. Could conceivably make it onto a ticket as a deputy if things get messy and a compromise candidate is needed.