One Nation is targeting a WA seat in Labor heartland. It could be a defining moment for Australian politics | Narelle Miragliotta for the Conversation

Where once a byelection for a state seat would have attracted little national attention, the remaking of the Australian political landscape in recent months has given such contests greater significance.

The next such byelection is on 29 August in the Western Australian state seat of Secret Harbour, triggered by the resignation of the Labor government minister Paul Papalia.

Papalia had represented the seat, and its predecessor electorates, since 2007. The area is Labor heartland, with the party’s two-party preferred vote averaging about 60%.

There is, however, the potential for a One Nation electoral upset. The seat has many of the characteristics that analysts identify as conducive to a One Nation victory.

Secret Harbour is an outer metropolitan seat on the southern coastal outskirts of Perth. Like many such electorates, Secret Harbour has high levels of mortgage and rental stress. One Nation polls especially well in seats experiencing high levels of economic anxiety.

The seat’s demographic profile has led William Bowe, a leading election analyst, to suggest its “low ethnic diversity and abundance of trades workers make it promising territory for One Nation”.

A portent of the threat facing Labor is the 28.5% swing recorded against its primary vote at the 2025 state election. Premier Roger Cook recently conceded it was “absolutely” possible the party would not retain the seat.

The Secret Harbour field

There are two features of the electoral field of note.

The first is that the Liberals are fielding a candidate. This might not seem unusual, except the major parties are known to engage in “strategic absenteeism” at byelections if there is a chance that a third (non-major) party or candidate might defeat the incumbent.

The Liberals’ decision to contest the byelection suggest they believe they are competitive. Also likely is that they are concerned about the optics of being a no-show in the race at a time when One Nation has established a branch in the overlapping federal electorate of Canning, currently held by the Liberal MP Andrew Hastie.

The second is the 16-strong field – nine more than at the 2025 state election. The field includes a regionalist party, several single-issue parties and six independents.

The ideological composition of the field is also noteworthy. Of the 16 contestants, more than half lean right, while four lean left. The composition of the field may signify something about the broader ideological direction of travel of the seat.

Opportunities and risks

Despite the large field, only three parties are the focus of media attention.

1. One Nation

It is remarkable that One Nation is even in contention given it gained just 8.4% of the primary vote at the 2025 state election.

One Nation’s prospects come off the back of the party’s popularity in national polls, and are supported by reports that WA Labor’s internal polling shows One Nation is competitive.

One Nation is also a big winner in relation to how-to-vote card recommendations. Of the six official how-to-vote cards registered with the WA Electoral Commission, only Labor is recommending voters rank One Nation below both major parties.

One other curiosity is that Turning Point Australia, a licensed franchise of Turning Point USA (an organisation that advocates conservative politics), has registered a how-to-vote card that supports One Nation, even though it is not fielding a candidate.

2. Liberals

The Liberal party’s prospects are not completely hopeless. According to DemosAU polling, the WA Liberals continue to outperform One Nation in statewide polls. Moreover, when the Liberals contested Secret Harbour in 2025, they won a 9.8% swing in their first-preference vote.

Yet, to the extent that social media spending can be considered a guide to the Liberals’ commitment to the contest, their investment in the campaign seems tepid.

Similarly, the WA party’s state leader, Basil Zempilas, imposed a modest metric to judge the party’s performance. He declared “a Labor loss will be a victory for the Liberals”.

The Liberals’ caution reflects their lack of clarity and consensus about how to address the One Nation electoral threat.

Whatever the outcome, the Liberals may find themselves in a political bind.

If the Liberals win the seat with preferences from One Nation, they will have to contend with One Nation claiming the credit. If One Nation wins, the Liberals will be accused of being in league with One Nation, and the outcome interpreted as further evidence of the decline of the Liberal brand.

3. Labor

As the party defending the seat, Labor has the most to lose in material terms from this election.

Labor is certainly taking the defence of the seat seriously.

It has announced major spending and policy initiatives, and there are reports it is spending $300,000 on its local campaign.

But the party’s zeal has not been without problems.

Its hyper-local, big-spending commitments have exposed it to accusations of pork-barrelling. Its efforts to maintain tight control over the campaign also made news for sidelining its candidate from speaking at some local campaign events.

Labor will struggle to retain the seat if its primary vote slips 5% lower than its vote at the 2025 state election (46.6%). This is even if the Greens’ vote holds up.

Implications beyond Western Australia

Byelections are not elections as usual. Held outside the normal electoral cycle, they are generally more localised in their focus, while turnout is often lower. Similarly, the issues and personalities at state elections do not always neatly translate to other election contexts.

Yet, amid growing electoral volatility, declining support for Australia’s major parties and the national rise of One Nation, the outcome could have significance well beyond the seat, with symbolic and practical implications for the direction of travel of Australia’s party systems.

• Narelle Miragliotta is an associate professor in politics at Murdoch University. This article was originally published by the Conversation