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. 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. There are also similar double dissolution provisions in the South Australian state constitution.