The constitution of Barbados, which came into effect on 30 November 1966, provides for a crown-appointed governor-general (who in turn appoints an advisory Privy Council) and for independent executive, legislative, and judicial bodies. The bicameral legislature consists of a Senate and a House of Assembly. The Senate, appointed by the governor-general, has 21 members: 12 from the majority party, two from the opposition, and seven of the governor-general's choice. The 28-member House of Assembly is elected at intervals of five years or less. The voting population is universal, with a minimum age of 18. The governor-general appoints as prime minister that member of the House of Assembly best able to command a majority. The prime minister's cabinet is drawn from elected members of the House of Assembly.