Sun Mar 22

One Nation’s surge and Liberal Party’s collapse in SA election reveal tectonic shifts in Australian politics

Written by: Rob Manwaring, Associate Professor, Politics and Public Policy, Flinders University

The tectonic plates of South Australian politics have fundamentally shifted. Peter Malinauskas’s Labor government has won a second term with a landslide win ^[1]. The final count should see Labor win around 33 seats in the 47 seat House of Assembly. This result dwarfs the Labor “Rann-slide ^[2]” of 2006.

The SA Liberals suffered a humiliating and record loss, reduced to single digits, with perhaps as few as six seats in the lower house ^[3]. The party will need to undergo a significant rebuild if it is to become competitive again.

The key story of the night was the insurgency of One Nation. The right-wing populist party has secured a higher primary vote than the Liberals, with a statewide total of 22%^[5] against the Liberals’ 19%.

In regional areas and One Nation’s target seats, the party came first in the primary vote count, and in the seat of Narungga ^[6] secured 37% of the primary vote. With unpredictable preference flows, the party could secure two lower house seats.

Key battlegrounds

Labor’s landslide came off the back of the Liberal collapse. Labor easily won a suite of metropolitan and suburban seats ^[7] such as Colton, Morialta, and Hartley, the latter of which saw former Liberal leader Vincent Tarzia lose his seat. Former Liberal strongholds, such as the seat of Unley, fell to a disciplined Labor Party headed by the charismatic Peter Malinauskas.

In the regions, the Liberal vote collapse was exacerbated by the dominant rise of One Nation. In a striking irony, it could be Labor preferences that secure some Liberal holds. The Liberals’ decision to preference ^[8] One Nation over Labor may also come back to haunt them.

One Nation has a realistic chance in two or three seats, such as Hammond ^[9]. As Pauline Hanson put it at One Nation’s after party, she has left a series of “landmines ^[10]” for the premier.

More pressingly, One Nation sees this as a springboard for the Victorian state election and the federal Farrer ^[11] byelection.

Fractures on the right

The conservative and right side of politics has fractured completely. There might be a temptation to see this as a one-off sugar hit for One Nation. Yet, this result has been coming for quite some time. The implosion of the SA Liberals is not a sudden phenomenon.

On polling data ^[12], the One Nation surge began at the start of 2026, in the wake of the December 2025 Bondi terrorist attack. Historically, the party has had limited presence in South Australia, often returning a primary vote of about 4%.

The SA Liberals have been in structural decline for some time, and this has been accelerated by recent events. The Liberal leadership churn has undermined the party’s standing, with four leaders in four years. The party has faced a number of scandals across a range of seats including Mount Gambier ^[13], Narrungga, MacKillop and Black ^[14].

More telling, and an under-appreciated issue, is that the party is no longer able to retain MPs. Former MPs such as Dan Cregan (Kavel) and Jing Lee (MLC)^[15] – both of whom left to become independents – are symptomatic of a party where its members feel increasingly unwelcome.

Liberalism running out of steam

One Nation has taken advantage of the ideological and factional instability of the Liberal Party. The conservative efforts to control the party has undermined unity and discipline. Shortly after Tarzia became leader, Conservative Ben Hood led the charge to ban late-term abortions. It led to an appalling debacle ^[16] with moderate Liberal MP Michelle Lemsink forced to jump into a taxi to fend off the vote, while on medical leave recovering from cancer treatment.

This incident was a form of payback from conservative Liberals who felt disenfranchised during the Marshall Liberal government (2018-2022), which saw a number of moderate legislative successes ^[17].

A key flashpoint on election night was the exchange between moderate Liberal federal Senator Anne Rushton and state Liberal MP Nick McBride. Wearing an ankle bracelet as he faces trial for domestic violence charges (an allegation he strongly denies), McBride argued the Liberals have far more in common with One Nation than they do with Labor. Rushton, in contrast, argued the party should actively pursue its “liberal values”.

Here is the ideological and strategic dilemma that state leader Ashton Hurn and federal leader Angus Taylor face. Conservatives will push the leaders to adopt One-Nation-lite policies to win back regional and former safe seats. Yet, moderates will argue that since the party is no longer in any meaningful sense a party of the city, it needs to radically overhaul its offerings to win back inner-city and more affluent suburban seats.

It’s far from clear what a re-energised Liberal Party could look like. Party leaders may well invoke the ghost of Robert Menzies or the formula of John Howard, but neither of these premierships offer much to a shrunken Liberal Party in a far more fluid and fragmented Australian polity.

It’s highly likely the One Nation insurgency is here to stay.