There is not much bipartisanship around in contemporary Australian politics. However, the Prime Minister and Opposition Leader are at one in the belief that Aboriginal and Torres Strait Islander Australians should be formally recognised in the Constitution.

Both Tony Abbott and Bill Shorten will attend a meeting in Sydney on July 6 along with 40 leading indigenous representatives. For those who support the cause, indigenous and non-­indigenous alike, this will be a crucial occasion.

As Megan Davis and George Williams acknowledge in their informative bookEverything You Need to Know about the Referendum to Recognise Indigenous Australians (NewSouth, 2014), “no referendum on this topic can succeed unless it has secured the broad support of the Aboriginal community and of their leaders”.

It is far from clear at this stage whether such broad support will be forthcoming.

The Joint Select Committee on Constitutional Recognition of Aboriginal and Torres Strait Islander Peoples, headed by indigenous Liberal Party MP Ken Wyatt, is expected to finalise its report before the meeting. Labor senator Nova Peris is deputy chairwoman of the ­committee.

Jesuit priest and lawyer Frank Brennan, a long-time supporter of indigenous causes, has proposed a modernisation of the Constitution that would eliminate the outdated ­notion of race and include an ­acknowledgment of the ­nation’s indigenous heritage and ongoing identity. Brennan’s case is detailed in No Small Change: The Road to Recognition for Indigenous Aus­tralians (UQP, 2014) and in his speech last Tuesday to the ­Sydney Institute.

As Brennan points out, “this is no small change; it is change which is necessary, correct and certain”. But it is “incremental change”.

Indigenous professor Davis addressed the Sydney Institute along with Brennan. She advocated substantial change that goes beyond the incremental.

Indigenous professor Marcia Langton, who was a member of the Expert Panel on Constitutional Recognition of Aboriginal and Torres Strait Islander Peoples headed by Patrick Dodson and Mark Leibler, delivered the Lowitja O’Donoghue Oration last Tuesday. Langton said the incremental change proposed by Brennan would not be supported by indigenous Australians.

Langton was reported in The Australian as saying: “Brennan suggests we remove section 25, amend the race power to become an indigenous power and insert a symbolic preamble; this kind of symbolic reform sets the bar too low.”

Brennan’s position is that, “not being indigenous”, he “respectfully awaits the decision of our ­indigenous leaders”. But his personal position is reflected in the question that he asks about how indigenous leaders would feel after a referendum: “Would they prefer to be working with our present Constitution which does not ­mention them or an amended Constitution which acknowledges them?”

Brennan is of the view that any referendum to recognise indigenous Australians in the Constitution needs to be held during the next term of parliament. He supports Saturday, May 27, 2017 — the 50th anniversary of the successful 1967 referendum that gave the commonwealth power to make laws with respect to Aboriginal people wherever they lived in Australia.

It also made it possible for Aborigines to be counted when reckoning the population of the states and territories.

The 1967 referendum on Aborigines achieved a record 91 per cent yes vote. The lowest yes vote was in Western Australia — at 81 per cent. There was not a no case presented.

In the 1967 referendum Australians were also asked to vote on a proposal that the nexus between the House of Representatives and the Senate be broken. The aim was to make it possible for governments to increase the size of the House of Representatives without increasing the size of the Senate.

The yes case was led by two political leaders who were very popular at the time, namely prime minister Harold Holt and Labor opposition leader Gough Whitlam. But there was a no case. It was put by two dissenting Liberals (Reg Wright, Ian Wood), two Democratic Labor Party representatives (Vince Gair, Frank McManus) and one independent (Michael Townley). All were senators. The yes vote went down in all states except NSW and achieved a total vote of 40 per cent.

The 1967 referendum demonstrated the difficulties faced when a referendum vote has a yes case contested by a no case. Even if those leading the no case do not have a high profile, as was the ­situation in 1967.

Liberal Party senator Cory ­Bernardi has indicated he will run a no case if the referendum goes ahead. Such a case may, or may not, receive public funding.

In the era of 24/7 news, this probably does not matter much. All the proponents of a no case need is access to television, radio, print and social media. They could get all the coverage they need essentially free.

Davis sees nothing significant in a 2017 referendum date. Brennan does, since he believes the issue will go off the boil, so to speak. It is not clear what some of the other indigenous leaders believe. It is likely Abbott and Shorten will want the matter dealt with when, in all likelihood, one or the other will be prime minister.

Any referendum proposal that extends specific rights to Abor­igines and Torres Strait Islanders is likely to be controversial and raise the question as to who is — and who is not — indigenous. As Brennan has reminded us, in her first speech in the Senate, ­Jacqui Lambie said she shared the “blood, culture and history” of Australia’s “Aboriginal traditional owners”. Clyde Mansell, chairman of the Tasmanian Land Council, rejected Lambie’s claim.

On Tuesday, O’Donoghue drew a distinction between the situation in 1967 and that of a half-century later. She commented that “there was a different movement to what it is now; (in 1967) black and white were together walking towards the path to referendum”.

It may be that the July 6 meeting demonstrates a unity among indigenous leaders that reflects the present unity on this issue between Abbott and Shorten. Or maybe not.