AUKUS, also styled as
Aukus, is a trilateral security partnership between Australia, the United Kingdom, and the United States intended to "promote a free and open Indo-Pacific that is secure and stable." Initially announced on 15 September 2021, the partnership involves two lines of effort referred to as pillars. Pillar 1 focuses on Australia acquiring nuclear-powered attack submarines and the rotational basing of US and UK nuclear-powered attack submarines in Australia. Pillar 2 entails the collaborative development of advanced capabilities in six technological areas: undersea capabilities, quantum technologies, artificial intelligence and autonomy, advanced cyber, hypersonic and counter-hypersonic capabilities, and electronic warfare; and in two broader functional areas: innovation and information sharing.