One of the remarkable features of the 2020 Defence Strategic Update is the clarity of its assessment of Australia’s strategic environment. Like all government documents, it is careful in its language but does not seek to hide the enormity of the challenges that changes in this environment present for Australia and the task of national defence. Its broad argument, which builds on the 2017 Foreign Policy White Paper assessments, is that the Indo-Pacific is changing profoundly. Over time, these changes may see the emergence of a strategic order very different from the one established in the period after the Second World War. This order was described in the 2017 Foreign Policy White Paper as the ‘rules-based international order’, an infrastructure of agreements, legal frameworks for dispute resolution, international institutions and assumptions animating diplomacy about how the world should work. The order, still largely in place but increasingly under threat, is underpinned by US economic and military power.