It is 48 years since the 1967 referendum. That referendum removed section 127 which said: "In reckoning the numbers of the people of the Commonwealth, or of a State or other part of the Commonwealth, aboriginal natives shall not be counted." It also removed the words "other than the aboriginal race in any State" from section 51 of the constitution which sets out the commonwealth Parliament's power, one of which was to make laws with respect to "The people of any race, other than the aboriginal race in any State, for whom it is deemed necessary to make special laws".

In theory, it meant that after 1967, the commonwealth could legislate for Indigenous people. In 1967 the 91 per cent of people who approved the referendum presumably thought that this would be a splendid thing for Indigenous people.

Alas, the people who crafted the referendum did not know enough constitutional law. Nor could they foresee the egregious nature of the Howard government's Indigenous affairs policies.

Those words "with respect to" in section 51 are very important. When the Howard government enacted its discriminatory intervention laws in 2007, they were challenged as beyond the power of the commonwealth because they were not for the benefit of Aboriginal people.

The High Court, as much in sorrow as in anger, held, quite rightly as a matter of constitutional law, that the words "with respect to" embrace laws which are detrimental as well as beneficial to Indigenous people, or indeed the people of any particular race the commonwealth wants to single out.

That is how Australia got a fundamentally racist constitution. And we have sat on our hands ever since.

We are talking about all this again in this anniversary week because the move is on to have another referendum on Indigenous matters in two years – the 50th anniversary.

The fact we are talking about it again tells us several things. First, the importance of getting it right, so the long-running sore does not continue to fester. Second, often referendums, like most laws, can have unintended consequences.

Further, the fact that an opinion poll suggesting 75 per cent of people favour a change in the constitution to recognise Australia's Indigenous people should be treated with caution. Time and time again, early opinion in favour of change quickly turns to opposition when the details are out.

This could quickly become the case with Indigenous recognition. This happened in 1999. A referendum to insert a preamble, which included the words: "honouring Aborigines and Torres Strait Islanders, the nation's first people, for their deep kinship with their lands and for their ancient and continuing cultures which enrich the life of our country", was defeated with 61 per cent of voters against.

The details in the latest move for Indigenous recognition will similarly cause a lot of trouble.

Some will say, what is the point of having Indigenous recognition unless section 51 is changed to make it clear that the commonwealth's power to make laws with respect to races is restricted to laws that improve the lot of those races.

And if you do that, why not have an anti-discrimination clause dealing with gender, age, sexual orientation, the disabled and so on. And if you are going to do that, why not have a full bill of rights like most other Western nations?

On the other hand, others, Prime Minister Tony Abbott and Father Frank Brennan among them, reject going beyond a recognition clause. Some just do not like the idea of rights in the constitution. Others think it will muddy the waters and could result in the defeat of the referendum – which would not be a good look for the nation.

Abbott says a recognition clause would not be changing the constitution, but "completing" it. What semantic, Jesuitical twaddle. Rather, it will be seen as a chance to fix a wrong, so it should be done fully and properly, and not passed up.

Brennan argues that changing section 51 to make it non-discriminatory would be "unachievable and unworkable". Well, it may be unachievable in the present environment, but it would not be unworkable. Many other nations have non-discrimination clauses in their constitutions. Many nations' courts, including our own, rule on what is or is not "discrimination" every day. Australia has plenty of anti-discrimination laws.

There is a real lesson from the 1967 referendum. Constitutional clauses (even newly inserted ones) often prove defective and need to be fixed.

What if the 1967 referendum had been differently worded to ensure the commonwealth could only legislate positively for Indigenous people? Does anyone image it would have failed, or even got less of a majority?

Maybe the reaction would have been incredulity that anyone could image the commonwealth doing such a dastardly thing as to enact discriminatory legislation.

Well, now it has. And that proves the case for a constitutional change to ensure it cannot do it again.

A preamble clause recognising Indigenous Australians would be absolutely hypocritical if the opportunity to remove all racism from the constitution were not taken.

The other racist clause is section 25 which says, "if by the law of any State all persons of any race are disqualified from voting at elections for the more numerous House of the Parliament of the State, then, in reckoning the number of the people of the State or of the Commonwealth, persons of that race resident in that State shall not be counted".

Sure, the clause has no practical effect. No state is ever likely to deregister from voting a whole race of people. But that is no argument for removing the clause.

It may have no practical effect but it is symbolic. And the whole point of Indigenous recognition is symbolic. The symbolism of constitutional recognition for Indigenous people would be meaningless or lost if the racist clauses are not removed at the same time.

If we have to wait beyond the 50th anniversary of the 1967 vote so be it. Unless we do the whole job the sore will continue to fester.

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