The decision the Maori Party will make, possibly today, on the disloyalty of Hone Harawira will have far-reaching consequences for the place of Maori in New Zealand's government.

Co-leader Pita Sharples put it powerfully at Waitangi on Sunday. "I believe if this doesn't work, if the Maori Party cannot establish itself as a bona fide partner in a government, then our chance is gone and probably there will never be another Maori party," he said.

Their difference with Mr Harawira has always been about partnership in government. Four of the party's five MPs want to be in a government. One does not. Possibly Mr Harawira would be happier in a different government but no party could rely on that.

He admits he regards himself primarily as an activist still rather than a politician. He remains happier leading a march than making the compromises of power. He maintains extreme positions that have no prospect of being satisfied because he wants to be in a position to demand better than the best that might be delivered.

That is a perfectly good tactic for a pressure group of any kind, and Maori have plenty of those. But now they have something more. For the first time in living memory they have a party in Parliament they can call their own.

They came into the post-war era with their parliamentary seats submerged in the Labour Party. When they became discontented with the Ratana alliance in 1996 the Maori electorates put their hope briefly in Winston Peters. When his party divided under the tensions of power it cut the Maori seats loose and they drifted back to Labour.

Meantime, a distinct Maori party, Mana Motuhake, formed by a Tai Tokerau dissident, Matiu Rata, had failed to make independent headway and was folded into an Alliance of left wing parties.

It was not until the most recent Labour Government deeply offended Maori voters with its foreshore and seabed legislation that an independent party was able to win Maori electorates. It was spurned by Helen Clark in 2005 but embraced by John Key in 2008.

National did not need the Maori Party's support to form a government and the Maori Party did not need the role he was offering. But it had merit for both. It gave National a possible friend for the future and gave the Maori Party a chance to achieve something - not least new foreshore and seabed legislation - that would be impossible from Opposition.

The Maori Party's gains have been modest but it stands to bargain for much more if this year's election gives it the balance of power. Mr Harawira might be able to persuade his colleagues to go with Labour instead if the party allows him to stay. But that only raises the question, why is he white-anting the party now?

If his stated concerns about its direction with National were genuine he would keep them quiet until after the election and voice them in the event that his colleagues chose to support a Key Government for a second term. The only possible purpose in venting his concerns now is to diminish the Maori Party's votes and make it less likely it will win the balance of power.

That purpose is completely in line with his stated preference to remain an activist on the sidelines of power, but it is not the role his colleagues want. They want the Maori Party to be taken seriously, to be "a bona fide credible partner in a government," as Dr Sharples put it.

If they expel him they run the risk that he will split the independent Maori vote in Tai Tokerau and possibly elsewhere, but Matiu Rata's experience suggests it is unlikely. If they do not expel him, he will assuredly continue to undermine their efforts from within. They know by now they cannot trust him. Cutting him loose would be best for all concerned.