'It's not enough': Why Chris Trotter believes Jacinda Ardern won't be the next Prime Minister

Jacinda Ardern knows she lost and shouldn't keep up the facade of being the Prime Minister in waiting, according to one of her strongest backers.

Historian and political blogger Chris Trotter told The AM Show in July it was up to Ms Ardern to roll Andrew Little as Labour leader or "inherit a ruin".

The very next day Mr Little stepped aside and she took over, a quick and clean transition at odds with the party's usually protracted leadership tussles.

Mr Trotter now says it's time for her to admit defeat, rather try to stitch together a Labour-Greens-NZ First coalition.

"She knows she's lost - 35, 36 percent is not enough," he told The AM Show on Monday. "Maybe the specials will bump them up to 37, 38… but whether it's enough to materially change things, I don't know."

He pointed out in 1949, Labour got 48 percent of the vote and still lost.

"Those numbers that we think are so good in the past would have betokened a decisive defeat."

Special vote impact yet to be felt

In recent elections the special votes have usually given the Greens an extra MP at the expense of National. With a record number of special votes this time around, some commentators have suggested both the Greens and Labour could get one, bringing the Labour-Greens bloc and National almost neck-and-neck. 

But Mr Trotter says the last two times Winston Peters held the balance of power, he went with the biggest party. In 1996 that was National and in 2005 it was Labour. This time, that will comfortably be National, regardless of how much the special votes help the left bloc as a whole.

"Bill English looks like he's going to become Prime Minister again with more votes than John Key won to become Prime Minister in 2008."

Election results

Former ACT press secretary Trish Sherson, appearing alongside Mr Trotter on The AM Show, said there was "no shadow of a doubt" National won the election.

"To change the Government, you actually have to take votes off the Government. Labour didn't do that," she said.

"I think this is a massive triumph for English... no one thought he would get anywhere near that huge result that Key managed to drag in."

She says NZ First could struggle as not just a minor party in a coalition with Labour, but siding with the smaller of the two major parties.

"A small party that throws their lot in with actually the losing side is not going to come out of it well."

 She said the Greens have blown their chance of getting into Government by siding so closely with Labour in the campaign.

"A vote for change could be a vote for a Green-National Government. If the Greens really want to be smart, they should be in Winston Peters' position now... They should have educated their membership on where they could go."

Chances of a Jacinda Ardern-led Government?

Mr Trotter puts the likelihood the Greens, NZ First and Labour will stitch something together at 25 percent.

Ms Sherson says it's "next to zero, at this point".

"I just don't think you can go against the will of the people."