The closure of the Strait of Hormuz in the US-Iran war has brought home how vital maritime trading routes are to a country like Australia, which conducts 99% of its global trade by sea.

Protecting Australia’s supply of critical goods – and exports of minerals, liquefied natural gas and agricultural products – requires maintaining maritime security across vast distances and countering threats far from Australia’s coasts.

This task is becoming increasingly challenging as China’s naval presence expands in the Indian Ocean.

Recently, a team of researchers from Stanford University, La Trobe University and Australian National University conducted a series of simulations to test the vulnerability of Australia’s economic and strategic lifelines.

We conducted a two-day war game involving nine former senior military and defence officials from Australia, India, the United States and Japan. The simulations tested the abilities of the Australian, US and Indian militaries to respond to two possible crisis scenarios involving China.

Our game demonstrated that maritime trading routes required protection across the full length of the Indian Ocean, not just in waters close to Australia.

For example, under certain conditions, we found even a single successful attack on shipping in the central Indian Ocean could severely disrupt trade across........

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