Earlier this month I published a blog post which discovered that the average 2CP margin of victory has not actually been getting smaller at recent federal elections. I didn’t end up including the chart in the post, but I also identified that the numbers of marginal seats hasn’t been going up over time, despite a number of formerly-safe seats now becoming marginal non-classic seats.
But I wanted to explore the make-up of those marginal seats over time, and the safe seats not included on the list: seats for each party, and the number of classic and non-classic seats.
A “non-classic” seat is a seat which ends up with a two-candidate-preferred count that is not Labor vs Coalition. These sorts of seats have been increasing in volume over time. A non-classic seat doesn’t necessarily mean that it’s a close race. Sometimes a minor party or independent makes it to the 2CP because the second major party is so weak (see One Nation in Maranoa). But the number of non-classic marginal seats has been growing over time.
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This chart is limited to seats with a 2CP margin under 6%. As of 2025, more than one third of marginal seats were non-classic. That’s 16 out of 46 seats.
So I then wanted to get a sense of how many seats for each partisan bloc are safe, or not safe. So that I could divide all seats into two categories, I’ve used 10% as the dividing line.
This first chart shows all seats held on margins of under 10%, split between the two major parties and everyone else.
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The party that wins the election tends to have more marginal seats, but the numbers have tended to be more even from 2007 to 2019, compared to earlier eras. The Fraser, Hawke-Keating and Howard governments usually held a significant majority of marginal seats after their elections.
The Coalition now holds just 30 marginal seats, their smallest number since 1966. That election was long before the expansion of the Parliament in 1984, and was also a very strong election for the Coalition. Their sparse number of marginal seats more reflected that so many of their seats were very safe. Labor’s numbers have been under 30 just once since the parliament was expanded: at the 1996 election, when the Coalition came to power in a landslide.
The next chart is a counterpart to the previous chart, showing seats held by margins of over 10%.
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It’s worth noting that the number of marginal seats notably increased when the parliament expanded, but the long term trend suggests that the number of safe seats didn’t change much when the parliament expanded.
When a party loses badly, they get hit particularly hard in this part of the pendulum. Labor did quite poorly in 1966, 1975, 1977, 2004 and 2013. Labor won just barely a quarter of the safe seats in 2013.
Yet no election produced a more lopsided outcome for a losing major party than 2025. The Coalition has just 13 safe seats, which is fewer than Labor held in a smaller House in 1975 and 1977. Labor also has more safe seats than either major party has achieved at any election since 1966. Indeed 1966 is the only election where a major party won more safe seats or fewer safe seats than 2025, but in the reverse direction.