Don Brash has just pulled off an audacious leadership coup against Act leader Rodney Hide, even more daring than his ousting of Bill English from the leadership of National in 2003.

Dr Brash has yet to be installed as the new Act leader but that will happen on Saturday with Mr Hide's resignation today.

Dr Brash joined the party today shortly before he and Mr Hide jointly fronted the press conference in Mr Hide's Newmarket office.

Mr Hide and the Act board were entitled to be offended at Dr Brash's method - an open declaration of a takeover more akin to hostile takeovers in business world, a repeat of how he did it with National.

But once the initial shock wore off, they were left with the power of the idea: either swimming with him or sinking without him.

The galling nature of Dr Brash's takeover will soon be forgotten.

The way Mr Hide has accepted his fate - "long live the leader" - has set an example to the board and Mr Hide's faction.

They will accept it too and spare the party any more of the destructive infighting that has bedevilled it for years - mainly over Mr Hide's leadership.

This post today by Act activist Cactus Kate spells out the infighting in gruesome detail.

Mr Hide will remain as Epsom's Act MP and the four other list MPs will remain list MPs.

Mr Hide will stay on as local government minister.

The manner of his going means that Mr Hide may reserve some options for himself come the next election as a possible list candidate. He has not made his intentions clear on that score and with a new wife and a new baby daughter, there's a good chance he hasn't decided yet.

There is no suggestion that the current confidence and supply agreement between Act and the National Government will be changed.

There will be no effect on Government stability in terms of the numbers.

But that does not mean there will be no effect on the Government in its relationship with Act in the short term.

Act will necessarily have a new relationship with the Government.

The quality of it will depend on how bold - or hostile - Dr Brash becomes in the seven months leading to the election to differentiate Act from National.

Much will also depend on how the new Act Party views the Government's record on race and Treaty of Waitangi issues - how carefully Key distances himself from that inevitable front without losing too much support to Act.

While votes for Act should not affect the total number of votes on the centre right, National will want to contain Act.

The more seats it gets, the more power it would demand as a support partner in a second-term Government.

The official line of National is that the leadership of Act is a matter for Act. The reality is that it is very much an issue for National.