Prime Minister John Key used to joke, when he was deputy leader to Dr Brash, about the Don-Key team. The joke has come back to haunt him.
Dr Brash took National from its worst defeat at the polls to nearly winning the Treasury benches in 2005.
Soon after, Mr Key rolled Dr Brash, who gracefully stepped away from Parliament. But that did not stop his drive for power.
National insiders wondered yesterday if Dr Brash had learnt anything from his first time of leading a political party. In an MMP environment, compromises had to be made, but when Dr Brash led National, it was his way or the highway.
Having talked extensively around New Zealand about closing the gap with Australia and chaired a task force which made strong recommendations about doing just that, Dr Brash had to endure Mr Key rubbishing the report as too extreme.
Dr Brash could cause a problem for National by taking some votes away from the party with his views on seabed and foreshore legislation, changes to health and education spending and government borrowing.
With his forthright views on race relations, a Brash-led Act could also do much to destabilise National's relationship with its other coalition ally, the Maori Party.
However, he could provide Mr Key with the opportunity to move National further into the centre, eating into Labour's middle-class voting base. Mr Key will happily leave any extreme views to Dr Brash, and Act, knowing he can water those views down after an election win.
Make no mistake, the money will come flooding back into Act now Dr Brash is in charge. Voters who remember the Iwi-Kiwi billboards may get something of a rerun in the lead-up to the November 26 election.
Dr Brash will tap into the white rump of New Zealand voters who believe the country is now too politically correct and soft.
