Australia's isolation is both its shield and its vulnerability

Marshall argues that Australia's vast surrounding ocean has historically functioned as a natural moat, sparing it the land invasions that shaped Europe and Asia, while also leaving it geographically remote from the allies it depends on. This isolation bred a particular strategic psychology: a country confident in its physical safety but perpetually anxious about being forgotten or undefended by distant partners.

That anxiety explains Australia's history of attaching itself tightly to a dominant naval power — first Britain, then the United States — rather than pursuing full self-reliance. Its enormous, sparsely populated northern coastline, close to Southeast Asia, is the one geographic feature that keeps planners uneasy, since it's harder to monitor and defend than the more populated south.

Marshall connects this directly to Australia's growing wariness of China: a resource-rich, thinly defended landmass sitting near a rising regional power revives exactly the old anxiety about distance from protectors. Isolation can protect you from invasion while still leaving you exposed to influence.