later than six months after passage. There is no similar time limitation if the bill is approved by one House of the Commonwealth Parliament only. To pass a referendum, the bill must ordinarily achieve a double majority: a majority of those voting nationwide, as well as separate majorities in a majority of states (i.e., 4 out of 6 states). This provision, which gives the small Australian states effectively a built-in veto, was one of those constitutional provisions accepted in order for the smaller colonies to agree to Federation. In circumstances where a state is affected by a referendum, a majority of voters in that state must also agree to the change. When a referendum question is carried, the amending bill is presented for royal assent, given in the monarch's name by the Governor-General. Territories Prior to the 1977 referendum, only electors in the six states could vote at a referendum. Since the 1977 amendment was carried, voters of the Northern Territory and the Australian Capital Territory have been eligible to vote in referendums. Territory votes are now counted towards the national total but the Territories do not count as states for the purpose of the requirement for a majority of states. Other aspects Voting has been compulsory in Australia since 1924. Similar to a referendum is a plebiscite, which is conducted by the government to decide a matter relating to ordinary statute law, an advisory question of policy, or as a prelude to the submission of a formal referendum question, rather than a binding and entrenched alteration (amendment) to the Constitution. Plebiscites can offer a variety of options, rather than a simple yes/no question. Four national plebiscites have been held as of 2017. Unlike in referendums, voting in a plebiscite has remained optional. In 1998, the Howard Government amended the Flags Act 1953 to require a plebiscite to change the Flag of Australia. There is some debate over whether such legislation is legally enforceable, and a new parliament could simply amend or repeal the legislation at any time. The No vote Australians have rejected most proposals for constitutional amendments, approving only 8 out of 44 referendums submitted to them since federation. Noting the difficulty of the referendum process, then Prime Minister Robert Menzies said in 1951, "The truth of the matter is that to get an affirmative vote from the Australian people on a referendum proposal is one of the