Double dissolution

A double dissolution is a procedure permitted under the Australian Constitution to resolve deadlocks in the bicameral Parliament of Australia between the House of Representatives (lower house) and the Senate (upper house). A double dissolution is the only circumstance in which the entire Senate can be dissolved.

Similar to the United States Congress, but unlike the British Parliament, Australia's two parliamentary houses generally have almost equal legislative power (the Senate cannot amend, although may reject outright, appropriation (money) bills, which must originate in the House of Representatives). Governments, which are formed in the House of Representatives, can be frustrated by a Senate determined to reject their legislation.

If the conditions (called a trigger) are satisfied, the Prime Minister can advise the Governor-General to dissolve both houses of Parliament and call a full election. If, after the election, the legislation that triggered the double dissolution is still not passed by the two houses, then a joint sitting of the two houses of parliament can be called to vote on the legislation. If the legislation is passed by the joint sitting, then the legislation is deemed to have passed both the House of Representatives and the Senate. The 1974 joint sitting remains the only occurrence in federal Australian history.

Historically, a double dissolution election has been called in lieu of an early election, with the formal trigger bill not playing a significant role during the subsequent election campaign.

Part of section 57 of the Constitution provides:

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