Would you like to see the incoming government be led by the Labour Party? If so, I suggest that you give your party vote to the Green Party. Please let me explain tactical voting.
It’s early August 2020 as I’m writing this and by the same time three years ago, there was no way that Labour was seen as having any chance of winning the 2017 general election. On 1 August 2017, the following graph was uploaded to Wikipedia that tracked the opinion polls, showing Labour trailing nearly 20 percentage points behind National.
In August 2017, few people predicted that Labour would form the government. In fact, National obtained the majority of the votes in the 23 September 2017 election. Still, Labour managed to eventually form the government by gaining support from two other parties that had also made it into parliament.
Coming back to 2020, few people give the National Party any chance whatsoever of forming the next government. There’s also a gap of 20 percentage points between Labour and National in the opinion polls; this time it’s just that Labour is on top. I suggest to you that the only thing that matters is the poll that will be taken on 19 September 2020. And how people will cast their vote may change significantly from where the opinion polls are currently at. The most likely scenario that could notably change voting preferences is another COVID-19 outbreak, especially if the opposition can successfully blame the government for mishandling the situation.
The Green Party is currently in an uncomfortable position, with opinion polls seeing them close to the 5% threshold that a party needs to reach to enter parliament (alternatively, they could also win an electorate; more on that later). Fact is, if the Greens get in, they will want to form a government with Labour. It may also happen that Labour needs the support of the Green MPs to form the government. If the Greens get less than 5% in the party vote, those votes are lost, and Labour may not be able to form a government. If enough Labour voters give their party vote to the Green Party, that will add at least six MPs to a Labour-Green government (each 0.8% of the party vote returns one MP; this varies from election to election and depends on the “wasted vote” and whether there are overhangs). Voting Green will thus ensure that Labour continues to govern.
A party vote for the Greens is a vote for a Labour government.Axel Wilke explains strategic voting, August 2020
Maybe a simpler way to explain it is that if you are in the “Labour-Green bubble”, the total vote count does not change if you vote for one or the other. It matters, though, when because of voting Labour, the Greens miss out on being in parliament. The graphic above explains it well. A party vote for Labour that leaves the Greens under 5% could mean that Labour won’t continue to govern.
Enough Labour voters giving their party vote to the Green Party is the best insurance policy to keep National or NZ First out of government.