Winston Peters' decision to back Labour in 2017 sowed the seeds for his ultimate demise, a political expert believes.
His party New Zealand First is struggling in the polls, despite coalition partner Labour's popularity, and faces being knocked out of Parliament in September.
The party launched its election campaign on Sunday, Peters saying over the last three years they had "opposed woke pixie dust" and "used common-sense to hold Labour and the Greens to account".
For their efforts, voters appear to have deserted them - dropping to 2.7 percent in the most recent Newshub-Reid Research poll and 2 percent in the more recent 1News-Colmar Brunton poll.
"It's very hard for a party that's in Government to attack that Government and attack what that Government's doing," Victoria University politics professor Bryce Edwards told The AM Show on Monday.
"He's been part of this, and that's the dilemma that all minor parties have coming out of coalition Governments, going into election years. Until now under MMP every minor party that's gone into coalition has subsequently done worse in elections, and I don't think this is going to be any different this year for New Zealand First."
NZ First knows this better than any other party. After helping form the first MMP coalition in 1996 with 17 MPs, in 1999 they were reduced to five. And after supporting Labour via confidence and supply in 2005 with seven seats, they won none in 2008.
Dr Edwards said the main pitch of their campaign launch was "we will stop things".
"It's a very negative way to try and get votes, and I don't think it's going to work."
SInce 1979, Peters has only spent six years not in Parliament - making him the eighth-longest serving MP in New Zealand history. Asked by host Duncan Garner if it was the end of the road, Dr Edwards said it likely was.
"I think it is time to start writing off Winston Peters and NZ First. Shane Jones must have some small chance of winning Northland, but I don't think so either.
"The two main polls this year have put them on an average of 2.9 percent. We saw nothing in the weekend to show that this party really has any ability to climb back up. A party needs some dynamism, it needs some sense of rejuvenation - we haven't seen this from NZ First for a long time. I think they really are running out of steam."
Peters, 75, has long positioned himself at the centre of New Zealand politics - able to work with either National or Labour. Before 2017, he'd sided with whichever party had the most votes - but that year he elected to go with Labour, which won 46 seats, compared to National's 56. Labour and the Greens' vote combined was also less than that of National.
"Those on the political right will punish him for that, and those on the left that want to reward him are just going to vote for Labour anyhow," said Dr Edwards. "He's lost both sides."
If National was still led by Simon Bridges or Todd Muller, he thinks Peters would have a better chance of re-election. But not now Judith Collins has taken the reins.
"With a resurgent National Party under Collins that's got their mojo back, those more conservative voters have got somewhere to go... She's been competent, she's had very good announcements... the reshuffle has been impressive for most people, I think. I've just never seen so much positive coverage of a National Party leader in many, many years - going back to the Key days.
"And even the negative stuff, where her opponents and critics - especially from the left - are criticising her, it's not in the way that they [criticised] Simon Bridges. Under Simon Bridges, Todd Muller, they were kind of laughing at him. Whereas at least the left are taking her seriously. They're scared of her, if anything."
But Collins still faces an uphill battle. National has been polling poorly since Labour's meteoric rise in the wake of the successful handling of the coronavirus threat to date. While Collins might stem the flow of voters looking elsewhere, Dr Edwards said at some point she has to find a way to win over undecideds.
"She's kind of shoring up that base at the moment, but at some stage she's going to have to shift back towards the centre. It could be difficult for her."
Voting in the election begins on September 5 and runs for two weeks.