I am spending time thinking about defensive strategies with the Chinese presence in the South China Sea and the Russian invasion of Ukraine. One area I am looking at is the first and second island chains, proposed by former diplomat and Republican John Foster Dulles during the Korean war, the strategy was to surround the Soviet Union and China with naval bases to project power.

So I am looking at the Australian defensive island chain consisting of the main Indonesian islands of Sumatra, Java, the Sunda islands, Timor-Leste, West Papua and Papua New Guinea. The islands of Kalimantan and Sulawesi provide further depth to the defensive island chain creating bottlenecks for approaching naval vessels. Naval vessels have to navigate chokepoints between the islands, this limits approaches from the north.

Australia has good relations with Indonesia, we have military cooperation and economic ties. Furthermore, Indonesia’s enhanced ability to defend itself also means they will not allow aggressive advances through its territory. This will be a naval manoeuvre, Australian air defences in the north of the country will pick off surface ships transiting through the Indonesian archipelago, so this would be a poor strategy.

Let us be under no illusions here, the threat to Australia is China, there is no other threat to Australian security. China now has assets in the South China Sea including runways and radar arrays on multiple islands. Will China attack Australia outright? Unlikely, however, with Taiwan under threat, the potential for the US and Australia to become involved is greatly heightened and an invasion scenario is now not out of the question.

An attack from the north is fraught with danger, this would then require attacks from the eastern and western flanks. As the majority of the population is based on the east coast, the Chinese security pact with the Solomon Islands is of grave concern, this could now become a spy station, naval base and logistical resupply base that endangers Australia.

This is highly concerning as merchant shipping passes through this chokepoint for the east coast, therefore, the first offensive target for the Australian military will be the Solomon Islands, they will have to knock out all their infrastructure. Indeed, they will flatten the islands. Whilst Prime Minister Manasseh Sogavare has stated there will be no Chinese military bases on the Solomon Islands, pretty much everyone except Sogavare himself knows this is not the case.

The north west has Christmas Island, Cocos and Keeling Islands with the Cocos Islands utilised as a naval replenishment site, an air force forward operating base, and radar surveillance site. This will prevent a force attacking the country from the north west, whilst the population is sparse, there are more potential landing sites on the west coast that will be unimpeded. However, logistic considerations and long travel times to major centres is an issue.

The harbour facilities that could be constructed on Cocos Island would have far greater potential than Christmas Island. There is a runway already, the island resembles Diego Garcia further west in the Indian Ocean operated by the US Air Force with B-1B Lancer supersonic bombers and B-52H Stratofortress bombers operating from the island. Cocos Island has the potential to operate early warning and surveillance aircraft routinely along with fighter aircraft as required.