Michelle Grattan | The high cost of the Liberals' Voice rejection for both Peter Dutton and the party

On Thursday, he made history again, quitting the Liberal Party over its decision to oppose the Voice at the referendum.

Wyatt, who lost his Western Australian seat at the election, had stood beside Prime Minister Anthony Albanese when last month he announced the wording for the referendum. In government, he had battled, against internal Coalition headwinds, to advance Indigenous recognition and a Voice.

Wyatt is a cautious, patient man. That he has left the Liberal Party is an indictment of his former colleagues. He told the West Australian: "I still believe in the Liberal Party values, but I don't believe in what the Liberals have become".

A day earlier, faced with a choice on the Voice between the mood in the parliamentary Liberal Party and the mood in middle Australia, especially among people under 40, Opposition Leader Peter Dutton opted for the party.

That was probably inevitable. After all, only days ago, after the Aston byelection loss, Dutton said his biggest preoccupation as leader had been holding the party together.

We can't predict what the Liberals' rejection of the Voice will do for the referendum, or, ultimately, for the opposition and Dutton's leadership.

Certainly it will be unhelpful for the "Yes" case.

The latest Newspoll shows the yes vote with an overall majority and winning in a majority of states - which it has to do in order to pass.

But the national "Yes" vote was only 54 per cent, and that is before the majority has been stress-tested by a campaign. There is a very long way to go in this marathon.

Dutton is often a pragmatist. Thus he was a driver of finding a way through the marriage equality issue. He hadn't been a supporter of gay marriage, but for him, settling the issue was more important than his personal view. Hence he promoted the idea of the postal plebiscite, admittedly a second-best route to just legislating first up, but a way of getting the job done.

If "Peter the pragmatist" had been uppermost, you'd think he would have sought a non-confrontational way through the Voice issue.

Senior Liberals could have been left to make up their own minds, as in the republic referendum. Dutton could have said he had reservations about central features of the government's proposal, but for the greater good - for the unity of the country and the pursuit of reconciliation - he would be voting "Yes" although not campaigning.

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Critics may or may not be right about the risks in the current wording of the constitutional change, which provides for the Voice to make representations to executive government. Equally, they may or may not be correct in claiming the Voice would make little difference to closing the gap.

But when Indigenous people have invested so much in the Voice, the question becomes: is the downside of denying it to them more damaging than the possibility of it being risky or impotent?

Some Liberals may be worried about its dangers. Others, more likely, just don't like the idea of it, or want to play politics, and would probably have rejected any wording. Too often, the Liberals simply like to say no, and dig in, as they did (and still do) over measures to address climate change.

A Liberal pragmatist who was also sceptical about the Voice might have calculated that if it were going to present as many difficulties as the critics foresee, it would be a (likely) second-term Labor government that would initially have to deal with them.

Dutton has promised to campaign against the Voice, but what does this mean? Will the Liberal Party be spending its scarce funds on the "No" campaign - money that could be better kept for the next election?

A few Liberal MPs, like Tasmanian Bridget Archer, are signed up to the "Yes" campaign. Others will be active for "No". A third group will prefer to keep their heads down, but could find themselves under pressure as the media compile lists of who is on which side and doing what.

The shadow minister on Indigenous Australians, Julian Leeser, has been left in an invidious if not an impossible position.

When he delivered a critique of the Voice to the National Press Club on Monday, Leeser suggested that Wednesday's party meeting mightn't make a final decision. (After all, a parliamentary committee is examining the legislation, and it's crazy to have a position ahead of that inquiry reporting.)

Leeser also indicated he favoured frontbenchers being given freedom to support either side in a referendum campaign. Instead, shadow ministers are bound to the party's decision.

Leeser didn't appear with Dutton at Wednesday's news conference. It was explained he had to return to Sydney for Passover.

As the relevant shadow minister, Leeser would be in high demand during the referendum campaign. How would he cope when he has serious reservations about the Liberals' position? Notably, Leeser said of Wyatt: "Ken is a profound moral voice. I feel immense sadness about his decision."

Jeremy Rockliff might not be a household name to many Australians, but the Tasmanian premier leads the sole Liberal government in the country. He is a declared "Yes" campaigner. Western Australian Liberal leader Libby Mettam has also declared for the "Yes" case.

Fred Chaney, a former federal minister for Aboriginal Affairs, has denounced Wednesday's decision as pandering to the most extreme elements in the party, and called on small "l" liberals - who he said had been "supine" in recent years - to follow Archer's lead in standing up for the "Yes" case.

Dutton's success in holding the Liberal show together has been strictly limited. And it has come at the cost of deepening the division in the country.