University of Newcastle political scientist Jim Jose says Australians will wake up with a "hangover" on Sunday when they realise they have rejected constitutional recognition of Indigenous people.
Opinion polls suggest the referendum, which asks voters whether they support constitutional recognition for First Nations people by establishing an Indigenous Voice to Parliament, is headed for a clear defeat.
"I think a lot of people are going to have that morning-after feeling of, 'This is not what I wanted' or 'This is not how I want to feel,'" Professor Jose said.
"I like to believe that voters get it right in the main, but this is one occasion, if the No vote is successful, and it looks like it is, that we will have made a mistake, and I'm not sure how we're going to be able to correct it in the short to medium term."
The referendum question arises from the 2017 Uluru Statement from the Heart, in which Aboriginal and Torres Strait Islander tribes called for a voice enshrined in the constitution and asserted an Indigenous sovereignty, or ancestral tie with the land, "which co-exists with the sovereignty of the Crown".
Professor Jose predicts Aboriginal and Torres Strait Islander people will regard a No vote as a rejection of their invitation to "walk with us" towards a better future.
"It will be interpreted by First Nations people as, 'We don't count', that the Australian voter has turned around and told us that we are not part of this country, we do not belong," he said.
"The impact on First Nations people who think about this and every day experience the micro-aggressions that come with racial issues, many of them will simply abandon faith in the political system to deliver anything for them.
"The Uluru Statement from the Heart was a statement in good faith about how we might do this differently, and basically the Australian people, in voting no, the message their sending, intentionally or otherwise, is rejecting the Uluru Statement from the Heart."
More than 2 million people have already voted in the referendum and almost 2 million others have requested postal votes.
Recent polls show support for the Yes campaign languishing at between 37 and 47 per cent.
Professor Jose said the international community would interpret Australia's rejection of constitutional recognition as a return to the White Australia policy of racial discrimination.
"This is the message that will go out to the rest of the world, that we do not want to recognise the First Nations people as having prior occupancy.
"Granted there are many in the No camp who want that recognition, but they've convinced themselves that making this a constitutional enshrining of the Voice is a step too far.
"For many Indigenous people, this will be a reassertion of the White Australia policy internally, and that's really unfortunate, because a lot of people, including First Nations people, have worked very hard to push past that history so that we can begin to come to terms with it without getting involved in rancorous and useless go-nowhere discussions."
The 1967 referendum on Aborigines being counted in the population and allowing the federal government to make "special laws" for Aborigines won bipartisan political support and 90.77 per cent of the vote.
Professor Jose said Australian politics had "gone backwards" since then, despite "many, many Australians wanting to do something positive" to improve outcomes for Indigenous people.
"The sort of politics which has played out over the past two decades has been one in which political figures have been quite content to denigrate those who might be different from us ... and the racial hostility that is generated has become worse over the past two decades."
He blamed senior Liberal and National party figures for "deliberately hijacking" the referendum into a debate about Anthony Albanese's leadership.
He said their attempts to stop constitutional recognition of First Nations people were "morally bankrupt".
"It's largely aimed at bringing down Anthony Albanese as the leader," he said.
"Senior people in the Liberal and National party are deliberately misleading the public to maximise their political advantage.
"It's now getting that Trump-ish element to it where they can say black is white, up is down, without fear they're going to be held to account."
