National Party politics - and, by extension, New Zealand politics - have suddenly become very uncertain. The nod to stability which outgoing Prime Minister John Key signalled on Monday with his endorsement of loyal deputy Bill English as his successor was shaken twice yesterday.
The first knock was delivered by Jonathan Coleman with his decision to make it a contest. A few hours later, Judith Collins entered the race, saying the party needed to broaden its appeal.
The three candidates represent quite different political strands. English, an MP since 1990, appeals to a sense of continuity and steadiness. He does not stand for the generational change which Coleman is promoting, but he has runs on the board as the author of eight budgets and an approach to political management which is competent and composed.
If he has a weak spot, it is that he has been judged previously by the electorate and was leader in 2002 when National suffered a crushing defeat. English learned from that humiliation, and is today a mature and skilful politician who would make a seamless transition from the Key era.
At 54, English has a career to reflect on, and enough time ahead of him to make his own mark. With judicious appointments to his team, especially in the role of deputy, an English-led administration could realistically hope to secure a fourth term for National, even without the undoubted selling ability that the Government will lose with the departure of Key.
Coleman, 50, is standing as a figure of change. The Health Minister lacks the profile of the other candidates, though not the ambition. He is indicating that, should he win, then a shake-up of the cabinet is likely.
There is room in National's ranks for new blood. Besides Key, several other ministers are calling it a day, which gives whoever succeeds scope to present a rejuvenated lineup to the electorate next year.
In a ministerial sense, Coleman is the least experienced contender but his handling of the often troublesome health portfolio has avoided blaring headlines which can corrode political careers.
Collins is the most polarising, fascinating and perhaps riskiest candidate. She comes with baggage that would have wrecked the career of a less ambitious and resolute politician, which perhaps explains her apparent appeal to the wider party.
At 57, Collins is the oldest contender but does not lack for energy and drive.
Throughout her career she has embraced a take-no-prisoners style. Three years ago she resigned from the cabinet in a controversy over the Serious Fraud Office, but returned when an inquiry cleared her name.
Her pitch is simple - the party, she says, needs to ensure its appeal is as broad as possible, and connects with men and women and all ethnicities. It suggests that she is best suited to reach beyond National's traditional constituencies at a time when political connection is fragmented and unpredictable.
The end of Key's political career presents National with an unexpected headache and suddenly means that Labour, as the largest Opposition party, is back in the race. It means that the caucus leadership vote could have a pivotal influence on the outcome of next year's election.