Once politics turned into a "cesspit", former prime minister Kevin Rudd had no option but to get out. Credit:Nicolas Walker At the memorial service for Labor legend Gough Whitlam, Rudd received a polite smattering of applause; Gillard received a raucous reception from the true believers. And while Gillard's popularity as Australia's first female prime minister grows, with a biography published and a series of speaking engagements, former prime minister Rudd has quit Australia. The family home in Brisbane is sold, Abby the dog lives with Jessica and Albert, and Rudd has moved to the United States. Until late January, he was based in Boston at Harvard University, while wife Therese Rein was based in London.

After selling her business Ingeus for $222 million to Arizona's Providence Service Corporation, the pair have been reunited in New York. Rudd's absence from Australia has been pronounced and deliberate, according to friend Frank Brennan, the Jesuit priest and legal scholar who has also been living in Boston. Politics in Australia had become a "cesspit", Brennan says, and "there was no way he could thrive as an individual…there was no option but to get out". He identifies a lecture at Harvard's Fairbank Centre for Chinese Studies on October 16, 2014, as the turning point in Rudd reinventing himself. The campaign to replace Moon, mostly undeclared, has begun and Rudd – the master of the undeclared campaign – is one of many jostling for position.

Beforehand "my reading is that he was wondering how he would go at such a high-powered institution. At a dinner after at the Harvard Club, with some of the leading international China scholars, he more than held his own," Brennan says. "A spark of the old Kevin came back." "He has been very disciplined, friends like myself have been counselling him, no matter how you are taunted by people in Australia, say nothing," he says. "That has helped with the healing, and with reorienting himself to realise he can have a second major career." Paula Dobriansky, a senior fellow at Harvard's Belfer Centre for Science and International Affairs and a friend of Rudd, says the former prime minister came to the university with the reputation as someone who had had a distinguished diplomatic and political career.

"By coming to Harvard he was able to not only reflect on it and share it with undergrads and grad students, who benefited, but at same time his tenure also afforded him ability to reflect on developments in Asia, with a particular focus on China, and its ramifications for the United States-China relationship," she says. Brennan says that, in the months after moving to Boston, the pair also found time to discuss their faith (Rudd was raised a Catholic but converted to Anglicanism when he married Rein)."He, like a lot of us, has delighted in Pope Francis, he reads everything Francis says. There have been times if Therese is in town they go to an Episcopalian church. But occasionally, when she has not been in town, we go off to the Catholic church," Brennan confesses. *** Back in Brisbane, Rudd has spent the morning painting with his first granddaughter, Josephine, and shows me the results. Of course, they have already been shared with his millions of Twitter followers. "After I left the Parliament the Harvard Kennedy School guys asked me to go and do this project, which is best entitled "alternative futures for US-China relations", he says.

"Namely, absent policy change either in Beijing or Washington which way is it likely to go at present, and, secondly, what are alternative credible futures which may be better equipped to preserve the peace for the long term?" Rudd says he has been back to Australia "several times, but not a lot. Therese and I have been travelling back and forth between London while I've been in Boston. The Boston flight is manageable and it's direct, but being together in New York will be more convenient at that level". "All the kids are either off working or at university, the need to be back in the country is much less and besides, if you've just left political life, it's far better to just exit the scene and not be some source of rolling gratuitous commentary." Rudd has "nothing to say" about Tony Abbott or Bill Shorten but can't resist talking about one of his pet topics, Labor party reform. "While I am no longer prime minister, no longer foreign minister, no longer a member of Parliament, I am still a member of the Australian Labor party," he says.

He wants all senate preselections to be conducted by statewide ballots and reduced union representation in the party, "commensurate with the unionisation of the work force". Such a move would amount to a cut to union representation from around 50 per cent of delegates to around 20 per cent – and trigger World War III within the party. *** In New York, Rudd is the inaugural head of the Asia Society Policy Institute. "It does not seek to emulate Brookings, or CIS or others by producing a ream of new publications – although we will publish some – in the tradition of think-do tanks we see ourselves as think and do rather than think and write."

The institute is also handily located up the road from United Nations HQ. And the post of UN secretary-general, which will be vacated on December 31, 2016, by incumbent Ban Ki-Moon, that observers say is what really interests Rudd. The campaign to replace Ban, mostly undeclared, has begun and Rudd – the master of the undeclared campaign – is one of many jostling for position. UN convention dictates the job is due to be rotated to Eastern Europe but this time around, tensions between Russia and the United States and Western Europe mean that a candidate acceptable to one could be vetoed by the other. If that happens, a candidate from the Western Europe and Other grouping – such as Rudd or New Zealand's Helen Clark – or someone from the South American group such as Brazil's President Dilma Rousseff​ or Chile's President Michelle Bachelet - could emerge as a compromise.

Clark, who is already ensconced in the UN bureaucracy as the head of the United Nations Development Program, has the support of current New Zealand Prime Minister John Key. Fairfax Media has been told Rudd will first need to demonstrate to the Australian government that he has the support of all members of the P5 Security Council – the US, China, Russia, France and Great Britain – before support is forthcoming. Dobriansky, like other friends of Rudd's in Washington, says she is not aware of the former Australian Prime Minister's interest in the job but adds "the UN could well use his strong global leadership and ability to forge consensus". And former Australian foreign minister Bob Carr goes further, declaring Rudd is "proving already a more plausible candidate than his critics in Australia are prepared to believe". "I attended a conference outside Abu Dhabi hosted by the UAE, he presented an overview of China, many of the themes would be familiar to Australians, but for Europeans and those from the Middle East, it would have been a useful distillation. He also clearly had a rapport with many of the people heading UN agencies and global NGOs. "

Brennan confirms he has spoken to Rudd about his interest in the post. "But as a mate I say to him, if it came to our part of the world, there is him and Helen Clark. But guess what, she is a woman [the UN has never been led by a woman], she is competently running a UN operation, the UN Development Program, and she wouldn't attract the same static from her own audience," he says. "If the world looked to our part of the world, I sure he would have an interest, but I think he would run a very good second." Journalist and author Nicholas Stuart, who has written two critical books on Rudd, says he doesn't think China would be willing to accept Rudd because he brings "the baggage of the past". Nevertheless, Stuart says "knowing the person that he is, I find it inconceivable to think that he would not desire to put his hat in the ring".

A spokeswoman for Rudd's old Department of Foreign Affairs and Trade confirms that he has indeed visited all of the P5 in the last 18 months and had had assistance with those visits. Rudd is emphatic he is not a candidate because of the UN's rotation system. "I'm sure across Eastern Europe there are those of more neutral persuasion. Who knows, we are 18 months away from that. But the bottom line is that the overwhelming consensus in the United Nations system is that it's a rotation to eastern Europe. Therefore it is not applicable to yours truly. That's kind of the end of it," he says. "I'm just being utterly pragmatic about it, that's just the bottom line. " ***

Rudd's post-parliamentary CV is already bulging with appointments and fellowships to universities and working groups in the US, Britain and China. "For me, you go on to the next phase of your public policy career. I'm not into the retiring business. I'm neither retiring, nor into the retiring business. They will take me out in a box." So does Kevin Rudd, tall poppy, miss Australia? "I'm not commenting on Australia, but what I'm saying is that in the United States, if you have an idea, a concrete idea which is capable of working whether it's in business or public policy the value of the idea commands its own respect," he says. "It is an encouraging and positive environment. I'm not saying that doesn't exist in this country but America is a vast country."