If anybody else in Labour is thinking about putting his or her hat into the leadership contest, they should think again. The flag has gone up on a serious contest that will determine whether the party will be fit for government in three years.
David Cunliffe and Grant Robertson have said yes immediately. They are in.
This is not the time for somebody who cannot realistically win to join the contest.
In last year's leadership race, Shane Jones was the self-indulgent runner. He joined as a way to redeem himself with the party, to ensure that his whole political career was not defined by blue movies.
This year's contest is likely to be more focused and more intense.
There was a feelgood factor in Labour's last leadership contest that won't be there this time.
It was the first time a vote on the leadership had gone wider than caucus and the contest itself energised the party.
There was no sense of desperation. They were around 33 per cent in the polls, which still had the left bloc within reach. Neither Cunliffe nor Robertson had a track record in leadership to attack or defend.
Everything has changed. The mood is dark after losing three elections in a row and posting the worst result in 92 years.
This time there is a record to defend and attack.
How can Robertson not use the 24.69 per cent Labour scored last weekend in the "only poll that counts" as an attack weapon.
Likewise it is hard to see how Cunliffe supporters can avoid raising Robertson's sexuality as a factor in his appeal to wider New Zealand.
It was easy for Cunliffe to smack down such talk when he was the favourite last year. It will not be so easy if the race is closer.
The contest will also be held in the midst of an internal debate about the party's future - whether it can equally represent the aspirations of middle New Zealand and the unions.
The leadership contest may be conducted in a civilised fashion but that does not mean it won't be brutal. Only serious contenders need apply.