The separation of powers is an important component of most modern democratic politic systems. In simple terms, the separation of powers requires that government be divided into three branches: the executive, the legislative and the judicial. Each of these branches must operate separately and no member of one branch should also be a member of the other. The purpose of the separation of powers is to balance and limit government power. Separating power prevents one person or group of people from accumulating or using too much power. The separation of powers also provides a series of checks and balances, so that if one branch of government overreaches its power or infringes on the rights of citizens, the other branches can intervene.
The concept of a separation of powers has a long history that can be traced back to the ancient Greek philosopher Aristotle. It is clearly evident in the Second Treatise of Civil Government, a 1690 political manuscript written by Englishman John Locke. However, the separation of powers is most commonly associated with a French political philosopher named Baron de Montesquieu. A jurist in his earlier life, in the early 1700s Montesquieu travelled widely in England, where he became an admirer of the British political system. In 1748 Montesquieu wrote The Spirit of Laws, which he described as a scientific study of government. In this book, Montesquieu described an ideal type of constitution, drawn from his understanding of the English constitution as it was in the early part of the 18th century. He identified three separate functions of government: what we today call the legislative, the executive and the judicial branches.
The idea of a separation of powers arrived at a critical time in world history. Both the American and French Revolutions drew on Montesquieu’s theory that government branches should be kept separate. The strongest working expression of the separation of powers was incorporated into the United States Constitution, which was drafted in 1787 and enacted in 1789. This constitution clearly divides government into three branches: executive (the President), legislative (the Congress) and judicial (the Supreme Court). It also includes a rigorous system of checks and balances. If one branch exceeds its authority or acts contrary to the national interest, the other branches can check (block) this. Some of the checks and balances in the United States Constitution include:
- Congress can pass legislation but the President can veto (block) this legislation.
- If the President does veto legislation, Congress can override this veto with a two-thirds majority.
- The President is commander-in-chief of the armed forces but only Congress can declare war.
- The President can appoint people to his cabinet but they must be endorsed by the Congress.
- Congress can impeach (put on trial and dismiss) members of the other branches, including the President.
- The Supreme Court can declare both the President’s executive orders and Congress’ legislation to be unconstitutional and invalid.
In contrast to the United States, the separation of powers in the United Kingdom has meant little more than an independent judiciary. Because the members of the executive (the prime minister, ministers and cabinet) are also drawn from the legislature (the parliament), there is not a strict separation of these branches of government. Yet the separation of powers is still an important feature of Australia’s political system. Like the United States Constitution, the Australian Constitution describes three functions of government and creates three institutions to exercise those functions. This is outlined in the first three chapters of the Constitution:
- Chapter I – the parliament
- Chapter II – the executive
- Chapter III – the judicature
Three sections of the Constitution allocate power to these three branches of government:
Section 1. The legislative power of the Commonwealth shall be vested in a Federal Parliament, which shall consist of the Queen, a Senate, and a House of Representatives, and which is hereinafter called “The Parliament,” or “The Parliament of the Commonwealth.”
Section 61. The executive power of the Commonwealth is vested in the Queen and is exercisable by the Governor-General as the Queen’s representative, and extends to the execution and maintenance of this Constitution, and of the laws of the Commonwealth.
Section 71. The judicial power of the Commonwealth shall be vested in a Federal Supreme Court, to be called the High Court of Australia, and in such other federal courts as the Parliament creates, and in such other courts as it invests with federal jurisdiction. The High Court shall consist of a Chief Justice, and so many other Justices, not less than two, as the Parliament prescribes.
The separation of powers in Australia’s State constitutions is less clear than in the Commonwealth Constitution. According to Carney (1993), the Supreme Courts in New South Wales, South Australia and Western Australia have ruled that the doctrine of the separation of powers does not apply in the States. The State constitutions do not contain clear divisions of power. For example, they do not create supreme courts or vest them with judicial power. Despite this, State practice on the separation of powers essentially mirrors Commonwealth practice.