Foreign Minister Julie Bishop will receive regular updates tomorrow night as votes are counted in New Zealand’s election. She knows if there’s a change of government across the Tasman the Australian media will want to interview her on Sunday morning. Their questions will be predictable after Bishop’s comments that she could not trust a future Labour government if, in Opposition, it had colluded with the ALP to reveal that Barnaby Joyce was a New Zealand citizen.

Two months ago, the ruling National Party appeared to be comfortably cruising towards a fourth term.

After the surprise retirement in late 2016 of popular PM John Key, there was a smooth transition to his deputy, Finance Minister, Bill English, who led his party to its worst ever electoral defeat against Helen Clark in 2002.  Despite this, his years running the country’s finances earned English a reputation for solid dependability. The baton change was followed by polls showing Labour trailing National by around 20 points.  Labour leader Andrew Little just wasn’t able to break through.

In July polls showed Labour’s support fall to 24%. Little fell on his sword and nominated his new deputy, 37-year-old Auckland MP Jacinda Ardern to replace him. This change was transformational for Labour.

With a high media profile since she was first elected in 2008, Ardern is widely known by just her first name – just like fellow “Kiwi” Barnaby in Australia.  She is seen as fresh, energetic and able to communicate with voters, and under her leadership Labour membership, volunteers and donations have increased sharply. Polls mid campaign showed Labour ahead with Ardern leading English as preferred PM.

So, will “Jacindamania” translate into an upset election victory? Ardern has made a huge difference to Labour’s fortunes but several polls in recent days give National a critical lead and show a clear late swing back to the government. Despite sometimes breathless coverage of Ardern this will be a very tough election for Labour to win.

National has a well-funded and finely-tuned campaign machine which rewarded it with extra votes at each of the past four elections. National has focused its campaign on stability, arguing that economic recovery would be threatened by a change.  English is well known to voters, having entered Parliament 27 years ago and most of that time occupying senior positions. Not renowned for his charisma, National have campaigned on him being the “rock” of stability.

There is no doubt National was caught by surprise by Ardern’s appeal and has been prosecuting a three-pronged attack, depicting her as short on specifics, that the team behind her is unqualified and that there is a fiscal hole in Labour’s spending plans. The government’s central mantra has been that Labour’s numbers don’t stack up and despite at times sounding shrill this has succeeded in getting the media talking about Labour weaknesses, stalling its momentum.

National is seeking an electoral reward for successfully taking the country through the GFC and returning finances to surplus. It is offering tax cuts, announced in the May Budget but not taking effect until after the election, and a big spending promise on road infrastructure. The difficulty for National is that apart from its commitment to tackle child poverty its promises are similar to those it has offered since 2005. It’s hard to see how they will generate additional votes at a time when National is fighting for its survival and chasing a big turnout in rural and provincial seats.

Labour is offering a cocktail of policies, values and identity politics, promising free tertiary education, the decriminalisation of abortion, climate action (which Ardern calls the “nuclear free moment of my generation”), cleaning up the nation’s rivers, expanding public transport including a high-speed train linking Auckland, Hamilton and Tauranga, a strong focus on housing affordability and a possible move to a Republic.

Labour’s key area of vulnerability has been taxation. The party is known to be sympathetic to a capital gains tax on property (excluding the family home). Ardern proposed to set up a Tax Working Group and was asking voters to give her broad backing to implement its findings.

She argued her generation was finding it nearly impossible to get onto the property ladder as baby boomers use their equity on rental property portfolios, crowding their children and grandchildren out of the property market. This appealed to younger Kiwis but the obvious risk was the reluctance of voters to give Labour a blank cheque to do whatever its tax inquiry recommended. National’s attacks hurt because late last week Ardern announced there would be no tax changes made during Labour’s first term.

Whatever happens on election night Jacinda will be smiling and thinking about tomorrow.

Voters targeted by Labour include women, young people and those living in provincial towns. Ardern has a particular appeal in Auckland among the younger professional set. Despite attention given to her upbringing as the daughter of country policeman, National’s private polling shows its provincial base is coming back to it.

For Ardern this election has no downside. If Labour falls short she will have revived her party as a viable alternative. She’s smart and with more leadership experience she should be on course for a big win in 2020. Win or lose a much bigger vote share means Labour MPs will keep their jobs and be joined by more colleagues, all under no doubt to whom they owe their positions. For Bill English, this is likely to be his last election. If he just scrapes back in there will be a sense that it was almost lost on his watch.

The dominance of the two major parties hasn’t left much room for smaller parties in this campaign but they are always important given New Zealand’s proportional electoral system.  The populist, anti-immigration New Zealand First will likely clear the 5% threshold and be the third largest party.  Although Labour’s resurgence has squeezed the Greens, they should also come in above 5%, very helpful to Ardern given their arrangement with Labour to “talk to each other first”. If the Greens fall below the line, there’s little chance of Labour taking office.

This leaves Winston Peters, leader of New Zealand First, as the politician most likely to decide the outcome, the third time he has been in such a role. Winston, another politician known simply by his first name, has a number of reasons to rattle National. He feels slighted by attacks it has made on him over the years, including recently about his eligibility for the pension (he is 72) while still drawing a parliamentary salary. However, he is a former National MP and unlike Ardern a social conservative and this might temper his thinking, especially if this is his last term in Parliament.

Peters’ choice will focus on whether he thinks it’s better for NZ First to prolong an existing government and force on it some of his populist policies or whether he wants to tap a mood for change. He knows that if he goes with Labour, Jacinda and not Winston will be the star. Peters is difficult to read and political pundits who have bet on what they think he will do have been embarrassed in the past.

The strong performance by Ardern means a change of government is possible but not likely. Whatever happens on election night Jacinda will be smiling and thinking about tomorrow.

Mike Rann, former Premier of South Australia, was a campaign strategist and speechwriter for David Lange in his 1984 campaign that defeated the Muldoon government in New Zealand. In 2012, he was appointed Visiting Senior Research Fellow at the Politics Department of Auckland University and is now a Visiting Professor at Kings College London.