It is 1999. Britney Spears and Whitney Houston top the charts and rapper Eminem introduces us to Slim Shady. We swap Pokemon trading cards and pat our Furbies. Keanu Reeves takes the red pill in The Matrix. And in Australia, we hold our most-recent referendum – on the question of the republic. It fails.

Even further back in our collective memory are the last referendums that were actually successful (about the retirement age of judges, among other issues). That was in 1977, the year the original Star Wars movie opened in cinemas, ABBA played the Sydney showgrounds in torrential rain and the late Queen celebrated her silver jubilee with a trip Down Under.

It’s no exaggeration, then, for Prime Minister Anthony Albanese to describe this year’s referendum on a Voice to parliament as a once-in-a-generation opportunity: it’s certainly a rare one. Many first-time referendum voters weren’t even born the last time around.

The idea behind the referendum took shape at the National Constitutional Convention at Uluru in 2017 and crystallised into plans to form an advisory body, known in full as the Aboriginal and Torres Strait Islander Voice, that would advise both parliament and executive government (which covers the public service), on relevant matters.

Critically, the government wants to enshrine the Voice in the Constitution. And since any constitutional change, amendment or addition necessitates that a referendum – a vote directly by the Australian people – be held, here we are.

So, how do you vote in this referendum? What has happened in referendums so far? Why is it a big deal?

First, do I have to vote?

Voting is compulsory for adults – you must enrol to vote if you are an Australian citizen and aged 18 or over. You can check your enrolment status here or enrol here. If you are already on the electoral roll for federal elections, you do not need to enrol again to vote in a referendum. There are exemptions for Australians travelling abroad, although most travellers are able to vote and are encouraged to do so, either with a postal vote or in person at some Australian embassies and consulates. Different conditions apply depending on how long you are away from Australia and whether the move is permanent or not. Some British subjects (those who were already on the Commonwealth electoral roll before January 26, 1984) can also enrol to vote.

Polling places will operate much as they do in federal elections: at local primary schools, community halls, childcare centres and the like, about 8000 in all. Many will no doubt be offering referendum sausages. You will be checked against the electoral roll in your electorate, but that is a technicality because your vote matters only on a state and national level, not locally (more on that later). You can vote early at a polling place if you meet certain criteria, for example if you wouldn’t be able to leave your workplace on polling day. Postal votes are also an option if you can’t get to a polling place on the day: applications for postal votes close at 6pm on the Wednesday before polling day. Apply online here.

The Australian Electoral Commission will also collect early votes from residential care homes, prisons and remote communities in the weeks before, sometimes by light aircraft, helicopter, 4WD, boat and barge. A telephone voting service will be available for people with low or no vision and for Australians working in Antarctica; there will be a number to call to register on the AEC website.

What will I be voting on, exactly?

Unlike a federal or state election, where there are typically multiple candidates, on this polling day voters will be asked to simply write the word “yes” or “no” in a little box in response to a single question.

The AEC has some discretion to decide whether a different kind of mark, such as a tick, could be valid, under what are called savings provisions, which allow it to count a vote when the voter’s intention is obvious. But the strong directive is to write the word in full to make your view as clear as possible. Your vote goes into a huge pot with everybody else’s from your home state (although if you reside in the Northern Territory or the ACT, your vote is only counted in the national tally. More on that below).

The question on the ballot paper will be this:

This amendment, which would be added at the end of the constitutional document, is intended to formally recognise Aboriginal and Torres Strait Islander peoples as the First Peoples of Australia, to establish the Voice to represent their interests and to give parliament the power to pass legislation related to the Voice.

All enrolled voters will be sent authorised pamphlets, as per referendum rules, outlining the No and Yes cases well ahead of time. These are already available on the AEC website here. The AEC also has a practice ballot paper here. And, in line with federal and state elections, all campaign materials must be appropriately authorised as required. If in doubt, check with the AEC here.

How is the vote counted?

Counting begins at 6pm on polling day, with a live tally fed to media outlets. If the count is close, it could be some time before a result is declared. Postal votes are given 13 days to turn up – which could be critical if the balance hangs on the result in one particular state.

To succeed, a Yes case must achieve what’s known as a double majority, endorsed by both a majority of voters nationally (including territories) and a majority of voters in a majority of states (but not including territories). This means if the results trickle in and there is no national majority, the referendum fails. If three states say no, the referendum fails. If the national Yes vote is above 50 per cent and four states say yes, it passes.

This is an intentionally high bar. “It should be made as difficult as possible to amend the Constitution,” said Tasmanian premier Sir Edward Braddon at a constitutional convention in 1897 when the rules for referendums were being decided. Note that smaller states were deliberately given the same power as the larger states, to prevent NSW and Victoria acting together against the interests of the rest of the nation.

Here is what the latest polling shows in each state and territory.

In Australia’s history, only eight out of 44 national proposals to change the Constitution have succeeded. Confusingly, often several referendums on different issues have been bundled together on the same polling day (each question put to voters is technically a separate referendum and is processed as such by the AEC). In 1913, voters were asked to make six separate decisions in referendums on trade and commerce; trusts; monopolies; railway disputes; corporations; and industrial matters. More recently, the 1999 vote packaged together a referendum about the republic and a referendum about inserting a new preamble into the Constitution. The Voice referendum, unusually, stands alone.

Do referendums generally favour a Yes or No case?

Australians can seem notoriously fickle when it comes to referendums, often voting against procedural amendments that, today at least, seem completely reasonable in hindsight.

In 1937, for example, after an unlicensed pilot flew around, over and under the Sydney Harbour Bridge, voters were asked to give the Commonwealth constitutional power to control aviation rather than leaving it with the states. Planes didn’t exist when the Constitution was first written. The Wright brothers made their historic flight in 1903 .

Opponents argued the amendment would somehow wreck state railway systems, bankrupt country towns and lead to higher costs for food and freight. “It’s insane to have completely different laws of regulating aviation in each state – we might end up with planes crashing into each other every time they cross the state border,” says Anne Twomey, Professor of Constitutional Law at the University of Sydney. “The arguments were absurd. Nonetheless, the referendum failed.”

We have also voted no to banning communists, changing the length of parliamentary terms and giving the Commonwealth control over the marketing of dried fruit. Generally, we have been loath to give the federal government more power over anything. Capriciously, however, we then voted yes to a mandatory retirement age for federal judges, Commonwealth control of social services and to amend the rules around filling casual vacancies in the Senate.

Constitutional experts say the electorate typically needs to be overwhelmingly convinced of the necessity of change. “Because you’ve got a binary choice of yes or no,” says Twomey, “for people who are just not interested and don’t care, the default choice is always no. That means you’ve got this layer of the people who are just not interested who are filling up the first 10 to 20 per cent of the No case before you actually get to people making a deliberative choice. It collects all the people who are just not interested and not prepared to turn their mind to it.”

Throw in competing campaigns from Yes and No camps, says Twomey, and some of those people who have indeed paid attention “are simply confused because a whole lot of misdirection is going on. People have raised scares and they may not necessarily believe the scares, but there’s just enough doubt and confusion out there that they’re not prepared to risk it.”

Why did the 1967 referendum succeed while the 1999 vote failed?

Contrary to popular myth, the 1967 amendment did not give First Nations Australians citizenship or the right to vote – they already had those rights. Its purpose was to remove two references to Indigenous Australians in the Constitution that were seen as discriminatory. Consequently, First Nations peoples would be officially included in the national census and the federal government was officially granted the power to make special laws on their behalf.

Even at the time, there were widespread misconceptions about citizenship and rights, says historian Bain Attwood, who co-wrote a book on the 1967 referendum with fellow Monash professor Andrew Markus. He suggests, though, that these misconceptions actually helped the Yes case: “There was a kind of certain truth to the story they told about citizenship. And not surprisingly, I think the campaigners were able to persuade voters that there was something in this.”

Significantly, because there was no opposition to the question in parliament, there wasn’t even a pamphlet produced for the No case, just for Yes. The referendum succeeded with a record 90.77 per cent of the national vote and a majority in all six states.

In contrast, the 1999 referendum on a republic with the Yes case headed by Malcolm Turnbull, faced strong opposition from a monarchist No case. That proposal emerged from the 1998 Australian Constitutional Convention and was announced by the then Commonwealth attorney-general Daryl Williams and the then special minister of state, senator Chris Ellison. The then prime minister, John Howard, personally opposed the proposed change, but had pledged to run the referendum if there was seen to be enough support for it.

There was confusion from the outset about what was being asked. Some voters thought it meant we would end up with a United States-style presidential system, “which of course, was wrong”, says Greg Barns, a lawyer who was campaign manager for the Yes campaign. “And then you had questions like, ‘oh, it’s going to be extremely expensive to change all the coins and the notes?’ And, you know, people can relate to that, and they say, ‘Oh, why are we doing this?’”

The national vote failed at 45.13 per cent; none of the states reached a majority.

And we were not to have another referendum for 24 years. The 2017 same-sex marriage plebiscite was not a binding constitutional referendum, but a national postal survey in which participation was voluntary. Following its Yes result, the parliament passed a bill legalising same-sex marriage.

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