Before the political firestorm consumes every ounce of oxygen in Canberra, let's consider Kevin Rudd's foreign policy performance.

As Foreign Minister, his work rate was prodigious. The ambition nearly as high. The self-confidence and the sense of conviction never flagged. The intensity was undoubted; only the ultimate intent was regularly questioned. This was the Foreign Minister of a middle power who ranged wide. Rudd asserted an Australian right to a voice over Libya and Syria with the same earnest involvement he brought to the big issues of the Asia Pacific.

Usually, a foreign minister is expected to have the confidence and backing of the prime minister. That could never be the case between Gillard and Rudd. Instead, Rudd stands with the handful of Australian foreign ministers who flew solo. The two that were most successful in this solo role were Spender and Evatt, which prompted a column early last year depicting Rudd as Evatt with a BlackBerry.

Rudd could never 'do a Hayden'; he could not, ultimately, settle for being a fine foreign minister in the service of the leader who'd robbed him of the top job. Rudd was, indeed, a fine Foreign Minister, but he found it hard to mention his Prime Minister by name. 

The personal tensions are so great, why did this strange arrangement hang together as long as it did? The answer goes to both policy and politics. 

Politics first. Rudd served as Foreign Minister to Gillard from the moment she formed a minority government in 2010 until now because the hung parliament meant she needed his vote as well as his talent. Plus, the foreign ministry was part of the deal struck at the death of Rudd's prime ministership.

Policy offers a broader and more interesting answer. Indeed, it is almost misleading to try to write of Rudd's performance as Foreign Minister, starting after the 2010 election. As Prime Minister, Rudd was his own über Foreign Minister, and so it is possible to talk about the almost seamless and consistent nature of the foreign policy of the Rudd-Gillard governments.

In the great struggle that is now in the open (a set-piece battle in caucus to be followed by prolonged guerrilla war) foreign policy will hardly get a mention. That is because the Gillard Government's approach has run smoothly along the tracks laid down by the Rudd Government.

Rudd's deep duality on China – great understanding linked to dark doubts – has driven Labor thinking. The self-proclaimed 'brutal realist on China' even put a score on his emotions about China: 80% positive and 20% negative. Gillard journeyed to Beijing following the Rudd script, seeking 'mutual respect' and claiming Australia's right to be 'clear and robust' in that conversation.

Gillard surprised some by embracing the US alliance with a fervour that matched that of enthusiasts such as Beazley and Rudd. The alliance continuum between the Rudd and Gillard governments has been more than seamless; it has actually built in intensity. On the alliance, even Tony Abbott can't attack Gillard from the right, much less her now-departing Foreign Minister. 

In the same vein, Gillard has stuck doggedly to the Rudd script on Afghanistan. The cracks are beginning to show in the Defence White Paper Rudd bequeathed to Labor, but this has more to do with equipment promises being mugged by reality than any significant Government wobbles.

Where foreign policy splits have appeared between Gillard and Rudd, they have been as much about personal positioning as policy difference: the snafu over the contract to run the international TV service (with the decision taken from the Foreign Minister and given to the Communications Minister) and the Gillard shift to sell uranium to India. Gillard overturned the ban that Rudd had maintained as Prime Minister. What was truly telling, though, was that the Prime Minister did the India deed without even telling her Foreign Minister. Gillard clearly did not trust Rudd enough to talk to him about a significant change in foreign policy; she feared Rudd might leak against her and the decision.

The India decision in November was a significant moment in the doomed dynamic between Gillard and Rudd. It signaled that basic trust and communication could not be maintained; that is a strange way to run foreign policy. Rudd was right to say in his Washington resignation speech that Gillard no longer had any confidence in him as Foreign Minister. All indications are that she was about to sack him.

So ends a strange period in the conduct of Australia's foreign affairs. Clear the field – let battle begin.

Photo by Flickr user United Nations Information Service - Geneva.