Jacinda Ardern has secured the greatest victory of any Prime Minister under MMP.
Set to win just a fraction above or below 50 per cent of the vote, her mandate materially exceeds the 47 per cent won by John Key in 2011 and 2014 - and is miles ahead of the 41 per cent won by Helen Clark in 2002 and 2005.
But that is only the beginning of the history-making nature of her win.
At 50 per cent, Ardern joins a pantheon that, since the 1930s, includes only the father of the welfare state Michael Joseph Savage (56 per cent in 1938), war leader Peter Fraser (51 per cent in 1946) and the scourge of the watersiders Sid Holland (54 per cent in 1951).
The only other names that stand alongside that lot are Joseph Ward (59 per cent in 1908), King Dick Seddon (58 per cent in 1893) and John Balance (56 per cent in 1890).
Ardern's triumph can be legitimately compared to such giants of New Zealand politics since it was won under MMP, which makes it much harder for contemporary leaders to win the huge shares of the vote of their first past the post predecessors.
Once the Greens' higher-than-expected 8 per cent is added in, Ardern's accomplishment indeed rivals the legendary Seddon, who ruled from 1893 until his death in 1906.
Ardern, now, can do anything she wants. She has an opportunity to deliver the transformation of New Zealand she has promised – and Clark before her – and lock in Scandinavian-style social democracy for a generation or more.
There is an opportunity to implement new taxes, such as on land, to deliver the expectations of her supporters for a more progressive tax system.
She could use such distributive policies to do the thing she said she is in politics to achieve (but has so far failed to deliver) – a big reduction in child poverty, at least on the relative measures she prefers.
It will be possible for Ardern to genuinely take a lead on climate change, which she described as her generation's "nuclear-free moment", rather than fall into line with the agriculture lobby's demands for protection from greenhouse-gas measures all other New Zealand businesses are expected to comply with. David Parker could be given free rein to resolve the vexed issue of the allocation of water rights.
If Ardern really wanted to stretch herself, she could look at a universal basic income that would resolve the problem of massive effective marginal tax rates that lock people in welfarism and poverty.
There is no reason for baby boomers to continue to be pandered to over the retirement age.
There are no excuses not to fire Phil Twyford and get someone into the transport portfolio to deliver Auckland the genuinely world-class rapid transit system it desperately needs.
Two questions arise. Do Ardern, Grant Robertson, Chris Hipkins, Megan Woods, Andrew Little and David Parker have the administrative competence to develop and implement the truly transformational agenda that the likes of Savage and Fraser delivered?
Second, do they have the will? There is nothing in Ardern and Robertson's record in politics so far to suggest their true ambitions extend beyond broadly managing the status quo. They have operated as incrementalists in the same way that meant Clark and Key left nothing like the legacy they could have.
Whether Ardern deserves her place in the pantheon will depend on whether she rises to the opportunities voters have now granted her to be the greatest Prime Minister in New Zealand's history.
Matthew Hooton is an Auckland-based PR consultant, whose clients have included the National and Act parties. These views are his own.