The cynic in me wonders if JA was always intended to challenge for this election and that Labour timed the events of the past few weeks to give her the best possible chance at challenging for a change in Govt.

With the crushing defeat of labour in 2014, a new leader was always going to be appointed, however, IIRC, she lost her seat to Nikki Kaye and was probably not yet in the position to challenge or be put forward for the leadership (also because more senior members of Labour were challenging).

Andrew Little was always a lame duck leader, no charisma, a union boy through and through, he was never going to unite Labour, if anything he was more divisive than any of them. At worst, he would do as he did, see labour drop in the polls and drop down his own ratings for PM.

Roll forward two years, Labours polls doing pretty much what had been predicted, JA rising quietly through the ranks to be promoted to deputy leader behind Andrew Little. All that was needed was then was something to spark life into the election. Disenfranchised voters needed something to rally behind, for a while that was the Greens and NZ First. National had pretty much peaked and the loss of Key meant that Labour had its best possibility in years to fill the "gaping personality hole" left by Key, Little was not that person.

Perhaps it was Labour that held the information about Turei, forcing her hand to drop the benefit fraud / election fraud bombshells, that started the buzz around the election. This was very closely followed by Littles last poll with Labour at its lowest point was his tipping point and what the strategists needed to then bring in "the shining light" of JA.

JA vs Key would have been an interesting battle, but I don't think she would have won on her "values" speel, Key would have been much more convincing in the debates than English, but JA vs English is a no contest, she proved she was no pushover, even though she was for the most part debating with little factual information.