Just politics or the ‘opposite of clever’? The risks and rewards of strategic voting

Vote splitting and parliamentary overhangs are not unheard of in New Zealand elections. But making them a deliberate campaign tactic is different.

Ads

As the pitch of the election campaign intensifies in New Zealand, a very particular species of political phenomenon has emerged: so-called strategic (or tactical) voting and its potential consequence, a parliamentary overhang.

This isn’t new, but the issue is creating more clamour than usual at this election because of the nature and scale of the strategic voting being advocated.

New Zealand’s mixed member proportional (MMP) system allows voters to choose their preferred political party via their party vote, but also use their second vote to select an electorate candidate – who may be from a different party.

And because of the “coat-tailing” rule, even parties that fail to make the 5% threshold for parliamentary representation – but win one or more electorate seats – are allocated a share of seats proportionate to their party vote.

Most voters give both votes to the same party. But vote splitting has been going on since the first MMP election in 1996, when New Zealand First candidate Tutekawa Wyllie took the Māori electorate of Te Tai Tonga while Labour won the party vote.

The best-known example was in 2011 when then-Prime Minister John Key had his famous cup of tea with then ACT leader (and former National MP) John Banks to signal he “wouldn’t be unhappy” if National voters gave Banks the Epsom electorate but their party vote to National.

That arrangement stayed in place for several elections and was pivotal to the parliamentary survival of the ACT party.

Vote splitting does not always produce overhangs. But when it does, to maintain overall proportionality, the number of list seats allocated to other parties is increased. This inevitably leads to a larger parliament.

If the overhang is big enough, it could also influence government formation: a bigger parliament increases the number of seats required to form a parliamentary majority, meaning a party with an overhang could skew the outcome.

And while this hasn’t yet happened in New Zealand, any talk of strategic voting raises that possibility.

From the cost of living and a health system under extreme pressure to how best to tackle climate change, the coming election involves some big choices.

This article is part of The Conversation’s Election 2026 series: expert analysis of the major policy debates and the big challenges New Zealand’s next government will face.

Coalition calculations

Overhangs have happened at half of the elections since 1996. On four occasions (2005, 2008, 2011 and 2023), this was down to Te Pāti Maori’s strong performances in the Māori electorates.

At this election, however, the concept of strategic voting to create an overhang has become a deliberate campaign tactic well beyond past examples.

Te Pāti Maori, for instance, is asking supporters to use their electorate vote for its candidates in the Māori electorates but to party vote for either Labour or the Greens. Party leaders argue this is the best means of increasing the number of Māori MPs, ensuring an independent Māori voice in parliament and changing the government.

To encourage this, the party has released a party list containing only its general secretary’s name – effectively nullifying its purpose. Using the electoral system to structure voter choice in this way is a new development.

On the right, there have also been calls for National-leaning voters to support the party’s electorate candidate but give their party vote to either ACT or New Zealand First. This is based on a relatively complex calculation of how best to engineer an overhang in favour of the current coalition.

Both National leader Christopher Luxon and his predecessor, Key, have dismissed the idea as “the opposite of clever”. They point to the risk of weakening National’s leverage in a second coalition government and potentially knocking senior, list-only candidates out of the race.

Party-specific considerations aside, creating a substantial parliamentary overhang – based on a partisan strategy that influences the formation of the next government – risks eroding public confidence in the electoral system in general. It could also create a parliament that doesn’t reflect the party vote.

After all, the move to MMP in the 1990s was in large part designed to counter the lopsided election results being thrown up by the old first-past-the-post system.

There are also concerns about whether a successful Te Pāti Maori vote-splitting strategy might erode public support for retaining dedicated Māori seats within the electoral system.

Read more: Election Policy Tracker: your guide to what the parties are promising during the 2026 election campaign

Overhang in the balance

The overhang issue became such a concern in Germany (which operates a similar MMP system) that in 2012 a federal constitutional court ruled large numbers of overhang seats violated electoral equality. German electoral law was changed in 2013 to award compensatory seats to parties disadvantaged by overhangs.

But this led to a significant increase in the size of the Bundestag (parliament). Between 2002 and 2021, it grew from 598 to 736 members, though recent changes have fixed the size of the legislature at 630.

There may be some here who would like this particular side effect. Former Prime Minister Geoffrey Palmer, for one, has long advocated for more MPs. He argues this would improve the quality of legislation and scrutiny of the executive.

But achieving this via a quirk of the electoral system – one that could have corrosive consequences for the legitimacy of democratic institutions – might not be the best option.

However, both the 2012 MMP Review and the 2023 Independent Electoral Review addressed this very issue and recommended abolishing both the coat-tail rule and the provision for overhang seats.

This would be complemented by lowering the party vote threshold to either 4% (the 2012 recommendation) or 3.5% (suggested in 2023) and fixing the ratio of electorate-to-list seats at 60–40 (because the steady increase in electorate seats over time has reduced the ability to deliver proportionality).

The future prospects of the incumbent government and the two major parties are not the only things riding on this year’s election. Depending on the size and impact of any parliamentary overhang, the future of the electoral system itself may be in the balance.
The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

Tags: Academic Journalism, The Conversation, The Conversation Academic News