“If deterrence fails – and war erupts – how does Australia intend to use its nuclear-powered submarines? They might expand Australia's choices, but they might also entrench it in operations Canberra would otherwise seek to avoid.” Bec Strating The twenty-seventh issue of Australian Foreign Affairs explores the costs, risks and potential benefits of Australia's plan to buy, build and operate a fleet of nuclear-powered submarines. Lost at Sea looks at the ways in which the AUKUS undertaking is set to reshape the nation's military, economy, diplomacy and foreign relations – and at the consequences and alternatives if the project does not go according to plan. David Kilcullen asks whether, and how, Australia could defend itself if the AUKUS submarines do not materialise. Peter Khalil looks at the capabilities nuclear-powered submarines offer and their potential to expand Australia's strategic options. Bec Strating explores what AUKUS says about Australia's ambitions within our region. Saul Eslake questions whether the massive AUKUS expenditure will produce meaningful economic benefits for Australia. Yee-Fui Ng analyses the legal risks and obligations Australia has accepted through the AUKUS treaties. PLUS Joel Backwell on Indonesia, Gorana Grgić on Europe's future and Natalie Sambhi on South-East Asia, and correspondence on AFA26's "Weapons of Choice" from John Kunkel, Naoise McDonagh and Shiro Armstrong.