Women, I think, are generally more self-aware than men and slower to put their names forward for leadership. In fact, they are reluctant to a fault. None of New Zealand's three female prime ministers so far have seemed exactly hungry for the task.
Jacinda Ardern sat out three Labour Party's leadership contests in 2012-16 before another big man, Andrew Little, virtually handed her the position. Helen Clark could have had the party leadership in 1990 when Geoffrey Palmer stepped down, if she'd wanted it then.
Doubtless she didn't want to carry the can for Labour's inevitable defeat at that year's election but a hungry man would have taken it anyway. In fact one did. Mike Moore survived to lead Labour to another election loss in 1993 before Clark stepped up.
Even Jenny Shipley, who toppled Jim Bolger in 1997, insists National colleagues urged her to challenge the sitting Prime Minister. Of course they all say that, but Shipley's coup was quieter and cleaner than most.
Judith Collins is the first female leader of one of our major political parties who has been conspicuously hungry for the job. She put up her hand when John Key departed in December, 2016, and again when Bill English retired in 2018, each time attracting little support from her colleagues.
It is hard to avoid the conclusion that naked ambition was the reason she was not more successful, especially in 2018 when she was running against Amy Adams, Simon Bridges, Steven Joyce and Mark Mitchell. And it has to be wondered whether a man would suffer in the same way. Nobody was more nakedly ambitious than Bridges.
But if Collins was not popular at Parliament it was a different story in the country at large. When the 2018 contest was under way it was fairly clear which of the five MPs was preferred among National people I knew. The one name spoken with enthusiasm was Judith Collins.
Those people would be part of what is loosely called a party's "base" and conventional wisdom holds that a major party needs a leader who has wider appeal. But National's support has been unusually large and solid for a party out of power, consistently around 44 per cent in opinion polls until this year.
Since those people were not voting for Bridges in the prime minister stakes they must have been voting for the party Key and English led. Will it be the same party under Collins?
National has always been a liberal-conservative party, liberal in the sense of individualism not socialism, conservative in its distrust of change. It is a coalition of liberals and conservatives on economics too. Liberals like free markets, conservatives like to intervene.
Whether its liberal or conservative instincts come to the fore largely depend on who is leading it. Key was a social liberal, less so on economics. English was a social conservative but economic liberal. Bolger led a very liberal government in social policy (Treaty settlements) and economic reform.
National has not really had a conservative phase since Muldoon was defeated, exactly 36 years ago on Tuesday, the day Muller stepped down and Collins took over.
Collins invites comparisons to Muldoon. Like him, she is "polarising", meaning she states her positions bluntly, which is thrilling for those who agree with her and dismaying for those who don't. And she is socially conservative. She was never a natural fit in Key's cabinet.
Key was a master of consensus politics. Faced with a question to which there seemed no safe, uncontroversial answer, he would invariably say something reasonable and satisfying.
The secret, he used to say, was, trust your instincts. It's easier said than done.
As he watched Muller struggling in recent weeks, Key reportedly contacted senior Nats with suggestions for how they could help him. My guess is that advice would be to give Muller more licence to be himself.
Muller always looked afraid to say something that had not been rehearsed with advisers. Leaders cannot operate like that. A prime minister has to make a call on many unexpected issues, large and small, every day in office.
Judith Collins clearly has not the slightest difficulty trusting her instincts and so far her instincts sound right.