The wave started when the Greens defended benefit fraud. Peters repaying his overpayment reminds us that Metiria Turia, who is still a Green candidate, has not.
Conditions were ideal for Labour. They just had the problem of their leader, until he fell on his sword.
In Jacinda, Labour have the ideal candidate for a five week campaign. Her regular Breakfast TV appearances have made her an accomplished TV performer.
The Maori Party is leaking votes to Labour too. Instead of campaigning on Maori water rights the party is campaigning for an amnesty for overstayers. They have lost the plot.
The only way to stop a tidal wave is to prevent it starting. Bill English and National's strategist Steven Joyce are just too cautious. National also underestimated Ardern. In Parliament she has been ineffective. In six years she has not landed a single attack on Paula Bennett. But none of this matters.
This is the age of celebrity politics. It is image not substance. Macron in France, Trudeau in Canada, Trump in America and now Ardern in New Zealand. The camera loves Jacinda.
The red T-shirt crowd we first saw on TV may have been Matt McCarten's "rent-a-mob" imported from overseas but mania when it gets going is infectious. Now the crowds are real.
I saw the Lange tidal wave. People came into my electorate office and took away handfuls of enrolment cards. On election day people lined up to vote in record numbers. Big enrolment and high voter turnout benefits Labour. As of June, the Electoral Commission estimated 445,234 voters (nearly all young and overwhelmingly Labour) had not registered. Last election just 76.77 per cent of those who did register voted. Labour strategists believe if they can lift enrolment and turn out, the party has 600,000 extra votes, enough to win.
Labour could be elected to govern alone. If the Greens, United Future, Maori and TOP all fail to reach the threshold then with the votes redistributed, Labour could govern alone on as little as 45 per cent. Winston Peters, confident he would be kingmaker, pulled New Zealand First out of the minor party debates. Now he finds himself in the middle of a benefit overpayment and is railing against "dirty politics". What is worse, when Labour does not need him Peters becomes irrelevant.
What could stop the Jacinda tidal wave? A major failure in the leaders' debates. Not likely. The Opposition Leader usually wins the leaders' debate.
Labour is doing its best to lose. The party is rolling out Andrew Little's ill-thought manifesto of promises the party never thought it would have to implement. In any other election promising to tax water, fuel, capital and tourism would be fatal.
All of Labour's new taxes are extra. Many of Labour's promises are just silly, such as trams up Dominion Rd. Others are reckless. "Nationalising" Maori water rights will prove very divisive.
If Labour continues to issue massive tax and spend promises for the next four weeks it may alarm the voters, though it seems nothing will turn the media against their love affair with Jacinda.
Elections are won by the party that sets the agenda. National wanted to make the management of the economy the issue. National has lost confidence in its strategy. It feels it must match Labour's spending promises with its own. If the election is not fought on who can best manage the economy but on Labour's agenda of housing, health and education, nothing will stop the Jacinda tidal wave. Five weeks is not long enough to discover whether Jacinda is too inexperienced and three years is going to be three years too long to learn the answer.
Richard Prebble is a former Labour Cabinet minister and a former leader of Act.