But didn't we fix this in 1967 with the historic referendum to include Australia's indigenous population in the Commonwealth?

Well, the 1967 did not do the job people imagined it had done - remove race from the constitution. Nor did it, as popularly imagined, give Aborigines citizenship or the right to vote. They came separately and earlier.

Nonetheless, the result was seen as a great symbolic vote greatly welcomed by indigenous people and the nine out of 10 Australians who at the time wanted an end to discriminatory laws against indigenous people.

But its full legal ramifications were not to become evident for nearly 40 years. No one then could possibly have known how John Howard would later turn the 1967 referendum result on its head.

We need to know more precisely what the 1967 referendum did before we can understand the need to revisit it.

The 1967 referendum made two changes to the constitution. First, it removed Section 127 which provided: ''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.''

The clause had been inserted because the number of representatives in the Parliament was to be determined by the number of people in each state. Victoria and NSW were suspicious that Queensland and Western Australia would get more representatives than they deserved if indigenous people were counted.

The simplistic (but incorrect) interpretation of the removal of Section 127 was that now Aboriginal people were counted it meant they had citizenship and the vote. In fact they already had those things. Indeed, white Australians as well only got citizenship in 1949. Before that they were ''British subjects''.

Voting rights are more complex. At Federation, the rule was those who were entitled to vote in state lower house elections were entitled to vote in Commonwealth elections - until the Commonwealth Parliament decided on any extension of the franchise. Well before 1967 the Commonwealth had done precisely that - giving indigenous people and women the vote even if they did not have the vote in some states in 1901.

Because the Commonwealth had done that, the odious Section 25 which mentions the possibility of a state excluding people of any particular race (not just indigenous people) was of no practical moment so no one thought to remove it in 1967.

The second element of the 1967 referendum was to change Section 51 (xxvi). Before 1967 it provided that the Commonwealth Parliament could 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 1967 the words in capitals were removed. It meant that the Commonwealth could make laws with respect to Aboriginal people.

The original section was intended in 1901 to let the states deal with Aboriginal people (usually badly) without Commonwealth interference. By 1967, in more enlightened times, it had the effect of prohibiting the Commonwealth from legislating to help Aboriginal people.

So the words had to go. But no one in 1967 seemed to have thought through the application of strict constitutional principles to the newly worded provision, and the beginning of John Howard's prime ministership was nearly 30 years away. The post-1967 provision gave the Commonwealth Parliament the power to make laws ''with respect to'' Aboriginal people. ''With respect to'' are crucial words. They are not restricted to ''for the advancement of'' Aboriginal people. They also embrace laws to the detriment of Aboriginal people.

No one in 1967 imagined the new constitutional provision would be put to such purposes, but then the Liberal Party was populated by decent old duffers like Harold Holt and David Fairbairn.

But in 2007 the Howard government enacted the intervention - an array of laws and regulations controlling many aspects of the lives of indigenous people. The Racial Discrimination Act had to be amended to allow the new laws to have effect.

A third, more subtle, effect of the 1967 referendum was to remove all references to indigenous Australians from the constitution.

So in 2010, the government promised to hold a referendum on indigenous recognition to finish the 1967 job. It was part of its pact with the Greens and independents.

Last month, the government postponed the promise for two years with agreement of the Greens and independents.

The government thought the people did not know enough about it and the referendum might be defeated. That would hurt the cause, rightly upset indigenous Australians, and cause us international embarrassment.

This week, Williams agreed with this. Williams is co-author of People Power: The History and the Future of the Referendum in Australia.

Williams argues in his book and again this week that in addition to bipartisan support, the people have to have a thorough understanding of the issues before you can expect a Yes vote. The present proposal has not had enough airing, he says. The proposal needs a definite timetable and date to get public attention.

But history shows that this, I am afraid, presents an impossible catch-22. The constitution provides a timetable for referendums which gives oodles of time for the Parliament and the people to refine, present and absorb the issues.

It should only require the slightest emergence from apathetic political slumber for people to find out about what they are being asked.

But our media cycle is not like that. Something a year or two away gets no attention in the commercial broadcast media. But if a referendum is to be held next week a vast babble of irrelevant fear and loathing dominates the airwaves.

And even though the proposal has been before the people for months (as it must be) the chronically apathetic Australian voter whinges; ''Why is all this being thrust upon us without enough time for us to get to understand it. If we don't understand it, vote 'no'.''

I don't think you can counter that media hype. You have to join it. An experienced media manipulator is required to create a whole lot of ''newsworthy'' events with lots of artificial newsworthy deadlines.

You then legislate as much of it as you can. And when after a few years the sky has not fallen in, only then do you ask the people to ratify the words in the constitution and only if you want the words there for symbolic (rather than legal) effect.

It is so difficult that, by and large, you have to rely on ordinary legislation for the bulk of constitutional change. We have been doing it for 212 years.

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