Going by recent opinion polls, the combined votes of National and Labour in the coming election may be the lowest ever – below 60%.

This might be a temporary dip, and the familiar National-Labour pendulum may swing back in future elections. Or it could signal a long-term trend. Results below 30%, or even 25%, will become normal for both.

Political fragmentation will see the “legacy” parties that dominated the postwar era shrink while others grow in size and number. Government formation will be more complicated.

This phenomenon is well advanced in many countries with proportional representation systems. The old left-right axis is intersected by environmental, economic and social concerns – from immigration and house prices to climate change and war in Palestine and Ukraine – that disrupt the old order.

For example, the Social Democrats won the most seats in Denmark’s 2026 election, but with only 21.8% of the vote. The Green Left party came second with 11.6%. The centre-right Venstre party fell to 10.1%.

Twelve parties in all won seats. A four-party minority coalition government, led by Mette Frederiksen’s Social Democrats, was sworn in ten weeks later.

In Germany, which uses a similar mixed member proportional (MMP) system to New Zealand, the conservative CDU/CSU coalition is now polling below 20%, and the Social Democratic Party below 15%. The populist Alternative for Germany (AfD) leads in the high 20s.

New Zealand’s 2026 election may represent a historic watershed in the evolution of a similar process.

If there is one issue unique to Aotearoa New Zealand that serves to illustrate the relative........

© The Conversation