When they squared off in parliament, Brendan Nelson used to think Kevin Rudd had a plan for the world.
He just didn't have one for Australia.
That's why the former opposition leader and ambassador now thinks Mr Rudd is "tailor-made" to lead the United Nations.
"I could spend quite a lot of time having a discussion with you about Mr Rudd's failings," Dr Nelson told the National Press Club in Canberra on Wednesday.
"But I think this is an occasion where we need to be at our best as Australians. This is a Team Australia event."
Some people are tailor-made for jobs.
"And I think Kevin Rudd's made for this job," he said.
When he was Australia's Ambassador to NATO, Dr Nelson took Mr Rudd to the North Atlantic Council during a visit to Brussels.
There Mr Rudd spoke to the heads of the military of the 28 NATO countries, the permanent representatives and senior political figures from those member countries.
"I sat at the top of the table as the Australian ambassador. Mr Rudd was next to me. And he wasn't good. He was stunningly brilliant," Dr Nelson said.
"Talking about Asia, the Asia-Pacific, the changing dynamic and I was proud to be an Australian."
Despite his glowing reference, Dr Nelson conceded it's not up to Australians but rather his prospective employers - the Security Council and the permanent representatives - as to whether he becomes secretary-general.
"It's up to the government, but I think we are Australians first, we are Australians last, he is an Australian, he's a former prime minister, he's got a natural instinct and skill in diplomacy that should be the envy of anybody that's ever worked in the diplomatic space.
"It doesn't mean he doesn't have enemies - he has a very long list - but, anyway, that's my view."
Foreign Minister Julie Bishop told the coalition party room cabinet would decide whether to support his nomination, but it would not be an endorsement.
Labor wants the coalition to back Mr Rudd, with deputy leader Tanya Plibersek saying the government would be incredibly small-minded not to do so.
Former diplomat Richard Woolcott, who served as Australia's top diplomat in the UN, agrees he should be supported.
Liberal senator Cory Bernardi understood some people will take a parochial position of wanting to support an Australian, but urged people to think of Australia's reputation.
"While Rudd is unlikely to win the position, how in good conscience, having lived through the Rudd leadership and destabilisation, can any of us suggest he is fit for the role he seeks?" he wrote on his blog.
"The world is in a difficult state. We face almost unprecedented levels of global debt, terrorism, social dislocation and a crisis of confidence in government. Whatever its failings (and there are many), the UN attempts to resolve some of those problems and needs the best possible leadership.
"Why would we make their job any more difficult by throwing Kevin Rudd into that mix?"
