The Commonwealth government was created with a Constitution patterned partly on the U.S. Constitution. The powers of the Commonwealth are specifically defined in the Constitution, and the residual powers remain with the states.

Australia is an independent nation within the Commonwealth. Queen Elizabeth II is the sovereign and since 1973 has been officially styled "Queen of Australia." The Queen is represented throughout Australia by a governor general and in each state by a governor.

The federal Parliament is bicameral, consisting of a 76-member Senate and a 150-member House of Representatives. Twelve senators from each state are elected for 6-year terms, with half elected every 3 years. Each territory has two senators who are elected for 3-year terms. The members of the House of Representatives are allocated among the states and territories roughly in proportion to population. In ordinary legislation, the two chambers have coordinate powers, but all proposals for appropriating revenue or imposing taxes must be introduced in the House of Representatives. Under the prevailing Westminster parliamentary system, the leader of the political party or coalition of parties that wins a majority of the seats in the House of Representatives is named prime minister. The prime minister and the cabinet wield actual power and are responsible to the Parliament, of which they must be elected members. General elections are held at least once every 3 years; the last general election was in November 2001.

Each state is headed by a premier, who is the leader of the party with a majority or a working minority in the lower house of the state legislature. Australia also has two self-governing territories, the Australian Capital Territory (where Canberra is located) and the Northern Territory, with political systems similar to those of the states.

At the apex of the court system is the High Court of Australia. It has general appellate jurisdiction over all other federal and state courts and possesses the power of constitutional review.

Australia maintains an embassy in the United States at 1601 Massachusetts Avenue NW, Washington, DC 20036 (tel. 202-797-3000), and consulates general in New York (212-408-8400), San Francisco (415-362-6160), Honolulu (808-524-5050), Los Angeles (310-229-4800), Chicago (312-419-1480) and Atlanta (404-880-1700).