Wherever Kevin Rudd goes, leadership speculation seems to follow. During his time in Australia, it centred on the stewardship of the Australian Labor Party. Now that he is based in America, it involves an even more disparate, unruly and opaque body, the UN.

According to a front-page report in The Saturday Paper, Rudd is positioning himself to succeed Ban Ki-moon as Secretary General of the UN, one of world diplomacy's most consequential postings. The South Korean, a career diplomat, ends his second term in 2017. Fueling the speculation, Bob Carr has chimed in by saying that Rudd would be ideal for the job.

A former diplomat, foreign affairs minister and prime minister, his curriculum vitae could almost have been written with the post in mind. His fluency in Mandarin would surely be a plus. Rudd has also mastered acronym-speak, the lingua franca of the UN. Already he has demonstrated his commitment to the UN by pushing for Australia's membership of the Security Council and serving on the Secretary General's high-level panel on global sustainability. Additionally, he served as a friend of the chair at the UN's climate change conference in Copenhagen back in 2009, a watershed event in his first prime ministership, if not in the fight against global warming.

Now teaching at Harvard, Rudd is a short shuttle flight from New York, and is geographically well-placed to launch a charm offensive. As with his return to The Lodge in 2013, the story, as recounted in Australia at least, has the ring of inevitability. After all, widespread is the feeling that Rudd's career has not yet reached its rightful fruition.

The problem with this narrative is that it overlooks some nettlesome details. In choosing its next head, the UN will adhere to a form of geopolitical correctness, whereby it gives each continent a turn. Having been led over the past three decades by a South Korean, a Ghanaian, an Egyptian, a Peruvian and an Austrian, the time has come for an Eastern European to take charge.

That is why so much speculation within the UN community in Turtle Bay focuses not on Kevin Rudd, but figures like Danilo Türk, the former president of Slovenia and international law professor, who served between 2000 and 2005 as UN Assistant Secretary-General for Political Affairs, one of the organisation's key jobs. Another name is the frame is Ján Kubiš, a Slovak diplomat who served as Secretary General of the OSCE and who now heads up the UN mission in Afghanistan. Rudd, as you will have noticed, is not the only potential candidate with an exemplary CV.

Even if it were Asia's turn, Rudd would face problems. The first is Australia's lock-step alliance with America, and his personal closeness to Barack Obama and Hillary Clinton. The glowing words from former Obama Administration officials like Kurt Campbell, who once described Rudd essentially as the American president's best friend on the international stage, would count against him. China and Russia, because of Rudd's alignment with Washington, would likely have strong misgivings about his candidacy, and block it with their vetoes. At the UN, the Permanent Five are even more powerful than the ALP's faceless men. Any of the P5 members can block a candidate in their enclave-like discussions, conducted largely behind closed doors, which end up recommending a candidate for the UN General Assembly to rubber stamp.

There is another reason why Rudd would struggle, if indeed he wants the job. With 'Kevin 747' airborne again, he would likely be a highly energetic and highly visible Secretary General. It is easy imagine him criss-crossing the globe trying to personally intervene in every flaring crisis. Though Ban Ki-moon racks up tens of thousands of air miles, he does so in a relatively unobtrusive way. Moreover, he's highly cautious (excessively so, some would argue) and seldom acts in a way that perturbs the P5 members of the deeply divided Security Council. Would Kevin Rudd show such restraint? Would he settle for inconspicuousness? Would he be bound by the will of the UNSC?

A weakness of his candidacy comes from the strength of his candidacy. He would attempt to do the job too well.

Such questions are, in any case, moot. A Cold War dynamic has returned to the UN Security Council since the annexation of Crimea. Rudd will be viewed by Moscow as being on the wrong side of the modern-day iron curtain.

Photo by Flickr user United Nations Photo.