Australia's National Security Act of 1939 authorised the federal government to make emergency regulations "for securing the public safety and defence of the Commonwealth [of Australia]". Further, it instructed the government to decide for itself what might be "necessary or convenient" for the "more effectual prosecution of the present war". This article examines the authorisation of the civilian leadership through one set of emergency regulations, the National Security (Women's Employment) Regulations, and analyses their functioning through one operational decision, the decision to permit women to serve in South Australian hotel bars with the intention of releasing male bar workers for essential industrial or military employment. Managing the home front proved complex. Sectional interests continued to jockey for positions of influence, even in war conditions. In this case, the state of South Australia sought to protect its "rights" against federal control of employment: a contest fuelled by an ideological squabble about what were then known as "barmaids". I argue that Australia's centrally-determined national war goals were undermined by its federal sovereignty-distribution mechanism, which allowed sub-national elements such as South Australia to impede national policy, and conclude that even with extensive defence powers to draw on, the federal government's war goals were obstructed by non-war interests.