South Australian election is likely to be Labor in a landslide. But who will be the opposition?

For the past six decades, South Australian politics has been characterised by long periods of Labor domination interrupted by short-lived Liberal governments. Since a record 32 uninterrupted years in office came to an end in 1965, the Liberal Party has spent a mere 17.5 years in government. Now, as they go to the election on March 21, the Liberals face yet another term (and probably several more) in opposition.

Led by Peter Malinauskas, Labor enjoys extraordinary levels of popular support. Solid, if unspectacular economic progress, combined with the aggressive pursuit of popular sporting events (AFL Gather Round, LIV golf, MotoGP) has left Labor in a seemingly impregnable position on the eve of the election.

And, as has been the case for much of the past 60 years, the Liberal Party’s ongoing internal divisions provide a sharp contrast with the professionalism of Labor. This in turn has rendered the Liberals an ineffective opposition and made the government’s task easier.

For example, Labor does not seem to be paying any serious political price for its failure to “fix” ambulance ramping at hospital emergency departments, despite this being a key plank in its 2022 election campaign that brought Malinauskas to power. Similarly, the growing level of state debt is apparently not deterring voters.

While the ascent of first-term MP Ashton Hurn to the Liberal leadership in December 2025 was overdue, it has not stemmed the fall in the the party’s polling. Hurn stood out in a very weak shadow cabinet as clearly the Liberals’ best performer. But the legacy of policy shifts and three leadership changes in a single term (one ahead of the prosecution of a former leader on a charge of supplying drugs) remains a continuing drag on the party’s fortunes.

Accordingly, there can be no doubt Labor will win yet another convincing victory. The election-night focus will therefore be less on the size of the majority, and more on how many seats the Liberals will be able to hold. There will also be much interest in whether One Nation can make a breakthrough in the House of Assembly.

Recent polls in SA have mirrored those taken elsewhere in Australia. One Nation now consistently outperforms the Liberals. But whether this will translate into seats in the state’s lower house is less clear.

The Liberals go into the election holding just 13 of the House of Assembly’s 47 seats. Six of these are in the Adelaide metropolitan area, and if any are lost (as several will be), they will be lost to Labor.

In rural SA, which has traditionally been dominated by the Liberals, they face threats not just from One Nation, but from several strong independent candidates who threaten to turn these contests into three-cornered battles. With a record number of candidates nominating, predicting the flow of preferences is difficult.

Read more: SA Newspoll shows Liberal wipeout likely; Victorian Morgan poll puts One Nation first on primaries

While polls show support for One Nation at somewhere in the mid-20s across the whole state, it may well be a little higher in rural electorates. Given One Nation received just 2.63% of the vote at the 2022 election (albeit standing in just over half the seats), this is a remarkable rise. It also reflects the growing disaffection with the Liberals seen across the rest of the country. At the same time, it may not be enough to budge rural Liberals from their seats as Labor preferences will probably come to the rescue of some beleaguered Liberals.

At the 2022 election, with one exception where there was significant support for an independent candidate, Labor won at least 20% of the primary vote in SA’s Liberal-held rural seats. With Labor preferencing the Liberals ahead of One Nation, to win a seat One Nation will need to either secure a substantial first preference vote or draw sufficient preferences from the minor parties and independent candidates. It could happen – but as long as the Liberals can stay ahead of Labor in the count, it is unlikely. If it does happen it will only be because the Liberal primary vote has collapsed, and in some seats the election of a high-profile independent is every bit as likely as a One Nation win.

On the other hand, in the state’s upper house, where members are elected under a proportional election system, all the signs are that One Nation will win two, possibly three seats. So, party defections aside, they seem sure to have some presence in the SA parliament for the immediate future.

So what might be the lessons for the rest of Australia? If support for One Nation on March 21 matches or exceeds their standing in the opinion polls, we will know the threat to the coalition is real – at least in the short term.

If One Nation fails to break through in SA, it will be largely a result of the particular circumstances of continuing high levels of support for the premier and the Labor Party.

But, with the exception of Western Australia, this combination of conditions is unlikely to be found across the rest of Australia. After the SA election, all eyes will turn to the byelection in the federal seat of Farrer, which is likely to tell us more about the changing shape of party politics in Australia.