If there can be such a play as a diplomatic tragedy, then the story of Kevin Rudd as a foreign-policy and defence-policy prime minister would fit the bill.

He had a far-sighted vision of Australia’s interests and what needed to be done to advance and protect them in a changing Asia and a changing world. He set out to do great things. But much went awry in the doing of them, and his legacy is less than it could have been.

Now reviewing my own hasty and somewhat harsh appraisal of his record up to 2010 in light of Rudd's retirement from parliament, I must admit to a few second thoughts.

For instance, while his rough handling of Australia’s relations with Japan and India amounted to an opportunity cost (we could have advanced those relationships further and faster), the damage turned out to be short-term and superficial, and we have all moved on. Gillard on India and now Abbott on Japan have helped see to that.

Rudd deserves a place in history for his ambition for Australian external policy. He briefly played Australia back into a significant place on global arms control efforts, and his International Commission on Nuclear Nonproliferation and Disarmament, though criticised by some, probably helped influence the debate in Washington towards a more restrained nuclear weapons posture (with more than a little help from Gareth Evans).

Rudd certainly recognised the big power shifts underway in Asia, particularly from the rise of China, and was ahead of the curve in identifying the risks from Chinese strategic assertiveness.

Back in 2009, some of us were more sanguine and have since changed our minds to recognise the need for increased Australian defence spending.

Nor was Australia’s rocky relationship with China in 2008 and 2009 all Rudd’s doing, by any means. Beijing’s misreading of Rudd as pro-China, and its subsequent exaggerated sense of betrayal, was a malfunction of Chinese diplomacy too. And by taking a stand against China on issues like defence policy, consular protection and human rights, Rudd certainly can’t be faulted for a lack of self-respect on his country’s behalf.

It is also to Rudd’s credit that he had mutually-reinforcing aspirations for Australian foreign and defence policy: we could wield bigger diplomatic influence in our region if we increased our own military weight.

Yet it is the very fact that Rudd’s agenda was so grand that makes its flawed delivery disappointing.

Much of the energy of his confusing Asia Pacific Community initiative was consumed in a flurry of airfares and thought bubbles, with Rudd first telling the region what it needed by way of diplomatic architecture, then asking the region what it needed, then discovering what many (including within the Australian bureaucracy) had known all along: that the region did not need a new forum, it just needed America and Russia to join an existing one, the East Asia Summit. They already had invitations pending, since 2005, and I still believe that their joining up was only a matter of time.

Still, it has to be said that none less than Hillary Clinton and Kurt Campbell have praised Rudd for doing more than anyone else to tilt the debate within Washington on this issue.

The gap between ambition and outcome is greatest, though, when it comes to defence policy. Whether one agrees with the entire force structure from the 2009 white paper – including a submarine fleet that will take decades to deliver at a cost that can still barely be calculated – it remains the blueprint for Australian military modernisation. It is yet to be seen whether the Abbott Government’s next defence white paper departs all that much in substance.

But Rudd’s defence plans will also be remembered for their failure to match capability with costings – and an almost immediate failure to follow through with the required budget.

In foreign and defence policy, as in domestic policy, Kevin Rudd’s performance will be remembered for its dissonance of promise and delivery. The wrong lesson from all this would be for future Australian leaders to overcorrect by attempting not much at all.