Australian strategic thinking has long struggled to move beyond a narrow view of defence that focuses solely on protecting our shores. However, in today’s world, our economy could be crippled without an enemy boot stepping foot on Australian soil.

Australia’s acquisition of nuclear-powered submarines through AUKUS marks a shift in this mindset.

It is not a strategy in itself, but a structural pivot: a recognition that our vital interests lie far beyond the coastline, and that defending them requires Australia to project its maritime power.

Over a century ago, US naval officer Alfred Thayer Mahan observed that “wars are won by the economic strangulation of the enemy from the sea”.

While not universally true, this maxim is directly relevant to an island nation like Australia – 99% of our international trade moves by sea.

But not just any trade – our critical supplies of fuel, fertiliser and ammunition all come by sea. Australia’s economy and defences would be crippled if these things were stopped at sea.

These vulnerabilities are compounded by our growing dependence on undersea cables for communications.

Strategic concepts that rely on making Australia’s territory a hard target, such as the “strategic defensive”, fail to grapple with this reality, perpetuating a flawed........

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