It's not often acknowledged but Key has studied what made Clark successful.
He once quipped to me - with just the slightest tinge of envy - that one of the things he most admired about Clark was "she has the Rolodex from heaven" built from the international relationships she made as prime minister.
Key was at that stage preparing to best Clark in the 2008 general election. She went on to cash in her valuable political chips - debts owed to her by the likes of Tony Blair to whom she lent much-needed support by agreeing to commit New Zealand engineering troops to Iraq with the proviso that the UN Security Council first crafted the necessary resolution - and leveraged herself into a successful bid to be the Administrator of the United Nations Development Programme. Key is adamant his heart is not set on the same type of post-political career that Clark has achieved.
He is prepared to put New Zealand's support behind her if she does contest the top UN job on Ban Ki-moon's retirement from the secretary-generalship.
But he is more likely to be setting the stage for a high-profile international governance career, perhaps sitting on the board of a Chinese bank or a sovereign wealth fund or a US financial institution. He is adamant that he has promised his wife not to take on another all-absorbing executive role.
Increasingly, he is building the necessary linkages.
For instance, at the recent G20 meeting in Brisbane he played a strong leadership role in the trade discussion by G20 leaders (at Tony Abbott's request) and made useful interventions in the discussions on the global financial system and some of the risks that lie ahead. These were acknowledged publicly by World Trade Organisation director-general Roberto Azevedo.
Key has also been invited as a contributor to the World Economic Forum meeting in Davos in Switzerland in late January. The WEF tends to invite leaders of G20 nations. But it also invites other leaders it considers influential, or whose countries are making a reasonable fist of economic leadership.
This will be Key's first time at Davos. It's a fair bet some of his holiday time will be spent making sure that the groundwork for his contribution is in place before he flies off to Europe.
His election as chairman of the International Democrat Union just before Christmas is also a major plus. It's likely the door to the IDU chairmanship was opened to him by former Australian Prime Minister John Howard.
Howard is "half a click" ahead of Key in the seniority stakes. He has been a mentor to Key since the latter was elected National Party leader while in Opposition. The National Party is one of 50 centre-right political parties that comprise the IDU membership. For Key, it will give him the opportunity to discuss centre-right policy prescriptions and importantly, boost his own Rolodex with high-level contacts from across the centre-right spectrum.
Already he has parlayed his golf game with Barack Obama into much more than a simple hit around the course. Being Obama's golf date gave him additional cachet including with Chinese Premier Xi Jinping whose first question on Key's last trip to Beijing was "Who won?"
In Clark's case she built strong allegiances through the Progressive Governance Group which numbered among its centre-left members Blair, Bill Clinton and former WTO director-general Pascal Lamy. She also navigated New Zealand's membership into the powerful East Asian Summit and notched up the trail-blazing China free trade deal.
Key's Government successfully managed New Zealand's election to the UN Security Council.
Both leaders have found their profiles rose as they went on to be valued senior member of forums like Apec and the East Asia Summit.
But the successes of our NZ political leaders offshore might be a tad prosaic. As Lamy reckons, New Zealand is among a group of countries whose international negotiating weight is "far beyond the numbers - not the big elephants, but people who can go between".
"It's like in business, if you are a clever interface you can get on both sides and it creates weight. Know-how, respect, consistency, openness, a sensitivity to human rights and the social environment acquired by nations like New Zealand lend this sort of actor a comparative advantage."
Clark has proven that. Key's opportunity lies ahead of him.
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