The doctrine of the separation of powers, involving a system of checks and balances, is basic to liberal constitutionalism. The system of checks and balances begins with the separation through a constitution of judicial, executive and legislative powers. However, it goes much further. It operates also within each branch of the state, in the division of powers between state and federal governments and the distribution of powers between the state, other institutions and individuals in the community. Within the legislative sphere, power is distributed between the component parts of parliament (Senate, House of Representatives and the Governor-General). The power of each House is diffused among its many members. A majority is necessary for the House to act. Each House has a different constituency and/or is elected at periodic intervals and is therefore constrained by the necessity of being responsive to the electorate.
Within the executive sphere ministers, besides having a duty to govern in the interests of the whole nation, are obliged to work with a public service. The impartiality of the public service (undermined in recent years) acts as a brake upon favouritism, corruption, discontinuity, nepotism and inefficiency. On the other hand, executive decision making and policy determination remain in the hands of the ministry. Under the Westminster system the ministry is further constrained by the reserve powers of the Crown and by ministerial responsibility to Parliament.
Within the judiciary, power is distributed amongst a hierarchy of courts in the context of judicial independence. The judiciary is the guardian of the constitution and acts as a check on the abuse of the executive and legislative powers.
Under federal constitutions there is also a division of powers between states and the central government...