Labor’s emphatic South Australian election win has quickly been overshadowed by Pauline Hanson’s One Nation surge and the collapse of the Liberal vote, with the result now raising broader questions for Victoria ahead of the Nepean by-election and the November state election.
While Labor secured the clear victory, much of the post-election focus has shifted to what happened on the conservative side of politics. One Nation surged ahead of the Liberals on primary vote and emerged as a serious force in both regional and outer suburban seats, intensifying scrutiny on the Liberals’ shrinking base.
Liberal Vote Under Pressure
The significance of the result is not simply that One Nation gained support, but that the Liberal Party appears to have been pushed aside in areas where it would once have expected to be the default alternative to Labor. The deeper story was not just a bad night for the Liberals, but a structural warning for the centre-right.
That is a party being structurally displaced across an entire state.
RedBridge director Kos Samaras made that assessment after noting how far the Liberal vote had fallen across multiple South Australian seats. He argued the pattern pointed to a broader political realignment rather than a one-off protest vote, with the shift strongest in outer suburban and regional communities shaped by cost-of-living pressure, economic frustration and anti-establishment sentiment.
Why Victoria Is Watching
That matters in Victoria because similar political conditions are already being discussed here. Rising dissatisfaction with the major parties, cost-of-living pressure and a broader anti-political mood have all created fertile ground for parties outside the traditional Liberal-Labor contest.
What happened in South Australia may not be repeated seat for seat in Victoria, but it has strengthened the argument that One Nation’s appeal is no longer confined to isolated pockets. That is what makes the coming Nepean by-election more than a local contest.
Nepean By-Election In Focus
The Nepean by-election will be held on Saturday, 2 May, following the shock resignation of Liberal MP Sam Groth in what is considered a safe Liberal seat on a 6.4 per cent margin. With Labor not contesting the seat, the result will be watched closely for signs of how much support One Nation can attract in Victoria before the statewide election in November.
On-the-ground observations by STPL News, along with broader media commentary, have already highlighted the significance of the race as parties and challengers position themselves ahead of the state poll. Nepean is now shaping as a crucial test not only for the Liberal Party, but for the broader political landscape in Victoria.
A strong One Nation result in Nepean would add further momentum to the party’s rise and strengthen the argument that the South Australian revolt against the Liberals is part of a wider realignment on the political right. It would not decide the November election, but it would offer an early indication of whether One Nation can convert broader dissatisfaction into a meaningful Victorian result.
Liberal Preselection Fallout
What compounds the challenge for the Liberals is that the party has entered the Nepean contest under a cloud of internal controversy. Anthony Marsh, the hand-picked candidate, had been a Liberal member for only a week before nominating for preselection, after senior Liberal figures reportedly moved to waive the usual two-year membership requirement that would ordinarily apply before seeking office.
That process has fuelled criticism from some local voters and conservative supporters who believe the party has sidelined its own base. Marsh has also attracted scrutiny because he previously positioned himself outside the Liberal fold and because his tenure as Mornington Peninsula Shire mayor has already been politically divisive on the peninsula.
That context is significant because One Nation candidate Darren Hercus is a former Liberal Party voter, while Libertarian candidate Peter Angelico comes from Liberal ranks. The result is a fragmented anti-Labor vote at a time when the Liberals can least afford it.
Much of the local conversation has centred on the same idea now emerging from South Australia: that the Liberals have drifted away from parts of their traditional base while trying to chase voters they may never win, leaving an opening for insurgent parties to capitalise.
A Warning Beyond South Australia
For Labor, the South Australian result is a reminder that a party can still win comfortably while deeper discontent grows underneath. For the Liberals, the warning is more immediate. The danger is no longer only losing votes, but losing their place as the default home for voters angry at government.
With Victoria showing signs of a similar political mood, the Nepean by-election is now shaping as an early test of whether One Nation’s South Australian breakthrough can carry into the state election campaign later this year.
