Stephen Grenville has provided an instant answer to Michael Fullilove's recent quest for a larger Australia: the addition of close neighbour New Zealand. This is annexation season further afield, but I am confident the Crimea option is not what Grenville has in mind. Instead, his argument potentially answers a perennial Australian question: New Zealand, just what are you good for?

But the answer is unlikely to be much extra size or heft. An extra four million people would be hardly noticeable unless they all crossed the Tasman and started demanding social payments. The two economies are already significantly (although not completely) integrated, and their Closer Economic Relations already acts as a stepping stone for broader regional cooperation (including CER-ASEAN).

And if Australia's foreign service is too small for the country's size and ambitions, as Fullilove suggests, then the addition of New Zealand's streamlined diplomatic corps would hardly overturn that numerical problem. Canberra may actually find the removal of a separate international vote for Wellington (in the Pacific Islands Forum, the East Asia Summit, and at the UN) a move backwards. Despite differences on some issues, two neighbours occasionally even find themselves in agreement.

And despite its obvious qualities, I don't think the New Zealand Defence Force is quite the answer to Fullilovian concerns that Australia is falling behind in Asia's strategic balance. We might bring some uncomfortably different views on China and the US too.

New Zealand is subject to periodic bouts of doubt about its future. That's on hold for now thanks largely to strong economic growth, which has attracted a fair bit of international attention and helped improve the net migration position. But we've not seen the last of it. And when it does return I don't think people here will be swayed by the argument that we should work towards a larger New Zealand: that might be too reminiscent of a not-so-glorious part of our history. Being small and smart, nimble and quick, are the sorts of myths New Zealanders treasure.

A larger Australia might just get the place that hundreds of thousands of expatriate Kiwis already call home into trouble. It could mean a larger carbon footprint, greater demands on limited water supplies, and expanding urban areas more vulnerable to larger bush fires. Indonesia does not want a larger Australia to deal with: it wants a more sensitive one. Australia is already the largest provider of aid in the South Pacific. But a greater understanding of the challenges of smallness could help Canberra's foreign policy in its immediate region. Getting bigger won't.

Australia could be twice as large and still not escape the asymmetries with growing Asian great powers or compensate for a decline in America's regional presence. Returning Aussie defence spending to 2% of GDP is less important than tackling the reluctance to prioritise in an already large capability plan and the political dependency that goes with it. The problem with Australia's international policy is not a lack of ambition. It is a lack of precision.

Photo by Flickr user Joe Shlabotnik.