In Australian politics, elections are not decided solely by primary votes. They are shaped — often decisively — by the flow of preferences. The Coalition's decision to preference One Nation ahead of the Greens in a string of marginal seats is therefore not a sideshow; it is the headline strategy.

The reasoning, briefed to backbenchers last week, is that the Greens-Labor alignment in the lower house has effectively created a two-bloc politics in which any vote that reduces the Greens' total is a vote that, eventually, helps the Coalition.

The arithmetic

In seats where preferences will likely decide the result, the difference between preferencing One Nation second and preferencing the Greens second can be worth two to three percentage points on the two-party-preferred vote. That is the difference, in modern Australian politics, between holding and losing.

Internal Coalition modelling shared with this paper suggests the strategy could net the Coalition between two and four extra lower-house seats, concentrated in outer-suburban Sydney and regional Queensland.

The political cost

The cost is the obvious one: every seat where the Coalition preferences One Nation invites the question of whether the Coalition is normalising the minor party. Several backbenchers have raised this concern privately; none has done so publicly.

"Preferences are the real ballot in Australian elections. Primary votes are the headline."

The party leadership's response, in private, has been pragmatic rather than ideological. The argument is that any party serious about forming government must, eventually, deal with the preference flows on offer.

What happens next

How-to-vote cards, the small printed leaflets handed out at every polling booth, will be the visible expression of this strategy. They will be printed in their hundreds of thousands in the next fortnight, and distributed to volunteers in the final week. Whether the strategy succeeds will, in the end, be visible only on election night.

The Greens have, predictably, called the move a 'cynical alliance.' Labor has been more measured, perhaps because the symmetric question — its own preference deals with the Greens — invites the same uncomfortable scrutiny.