Constitutional framework
The Compact completed the transition from the 1946 elected transitional Parliament to ordinary parliamentary government and established a prime minister responsible for ordinary national administration. The Commonwealth remained a monarchy, with the sovereign as head of state and the governor-general as the sovereign's representative in Australia. It had no president.
First prime minister
The first prime minister, Nathaniel Mercer, had served as an Army engineer before working in wartime production and reconstruction. He relinquished his service appointment before taking civilian office in 1949. His technical-service background shaped the first government's emphasis on public education, machine tools, reliable utilities and long-term scientific investment. Mercer treated the strength of the armed forces as an outcome of national productive capacity as well as military spending.
Reserved powers and court approval
The Department of War nominated the governor-general through a statutory service council. The Crown formally commissioned that nominee under the constitutional settlement. Morshead remained the first governor-general until 1954. Before the governor-general could dismiss a government, the High Court had to confirm that the specified constitutional grounds existed. Only then could the service council authorise dismissal. Disagreement over a budget, election result or policy was insufficient. Ministers governed through a House of Representatives apportioned principally by population and a Senate with equal jurisdictional delegations. Every state and territory received a voice in both houses, with representation of remote external territories arranged through statutory territorial rolls. The judicial condition restrained the military guarantee, although the reserved power remained a limitation on parliamentary independence. The military guardian clause became permanent under the Compact, with annual parliamentary scrutiny of its use and administration. Permanence did not waive prior High Court certification or permit the services to dismiss a government simply for losing their confidence.
Ministers controlled budgets, public services and legislation. Military commanders could advise and exercise the reserved constitutional powers, but they could not simultaneously command operational forces and serve as parliamentary party leaders. Officers entering politics first relinquished their commands. The 1949 settlement and Australia Sovereignty Act thus ended direct junta administration and remaining external legislative and appellate authority while preserving a military guarantee over the political system.
Parties and political competition
The Commonwealth Defence League became the shared political movement. Within it, independent parliamentary parties competed over public ownership, taxation, welfare, business regulation and the pace of territorial development. The Social Service Party occupied the centre-left; the Commonwealth Development Party held the centre; the Defence and Enterprise Party occupied the centre-right. These parties formed the principal parliamentary organisations of the new settlement.
All League parties accepted national service, the Crown, equal legal protection, the territorial union and the maritime defence programme. The former Labor, Liberal and National organisations did not survive as national governing parties, and a Greens party did not emerge. Environmental, labour and civil-rights arguments instead developed inside the permitted parties and outside Parliament through civic organisations. Surviving leaders of those former organisations retained their permanent advisory role outside Parliament; the Council could submit recommendations but could not vote in either house.
The resulting system was a restricted parliamentary democracy under military guardianship. Elections mattered, governments could change and parliamentary opposition existed, but national voting rights depended on service and the military retained dismissal powers subject to prior judicial approval. American unease centred on those restrictions and on Australia's independence in defence policy. Shared security interests nevertheless drew Washington and Canberra into sustained cooperation.