2023 Aston by-election

The 2023 Aston by-election was held on 1 April 2023 to elect the next member of the Australian House of Representatives in the electorate of Aston in Victoria.

The by-election was triggered by the resignation of Liberal MP Alan Tudge, on 17 February 2023.

The ABC's Antony Green called Aston for Labor at 8:16 PM AEDT, for the Labor candidate Mary Doyle. The result was considered a historic upset by the media. Aston had been regarded as a safe seat for the Liberals, and had been held by the party since the 1990 federal election. It marked the first time in 103 years that a government has won a seat from the opposition in a by-election.

Background
Aston had been considered a safe Liberal seat during Tudge's tenure as MP, until becoming a marginal seat at the 2022 election. News of Tudge's resignation prompted speculation that former treasurer Josh Frydenberg, who lost his seat of Kooyong at the 2022 election, would seek the Liberal Party endorsement for the by-election. However, Frydenberg declined to seek re-election, having since moved to the private sector.

The by-election was quickly labelled as key for the Coalition who are in opposition at the federal level and have performed poorly in recent Victorian elections. As of the date of this election, the last time a government had won a seat from the Opposition was the Kalgoorlie by-election in 1920.

2022 election result
Tudge suffered a two-party-preferred swing of 7.3% against him at the 2022 election. His Labor opponent was Mary Doyle who would later win this by-election. The Greens also contested the election and had a 3.2% increase in primary vote from the previous 2019 election. Other parties that contested Aston at the 2022 election were United Australia Party, One Nation, Liberal Democrats and TNL, and each of them achieved less than 10% of the primary vote.

Candidate selections
On 17 February 2023, the ALP selected Mary Doyle as its candidate for the by-election. She had been the party's candidate against Tudge at the 2022 federal election and won preselection unopposed.

On 21 February 2023, the Liberal Party selected Roshena Campbell as its candidate for the by-election. She was selected by the state party's administration committee, a decision taken to avoid the lengthy process of a members' ballot given the relatively short timeframe of the election. If she was elected, Campbell would have been the first female Indian-Australian MP from the Liberal Party. Other candidates for Liberal Party preselection included former state Liberal MP Cathrine Burnett-Wake, former Knox City mayor Emanuele Cicchiello, and oncologist and writer Ranjana Srivastava, who was endorsed by former premier Jeff Kennett.

At the time of their preselections, neither Campbell nor Doyle lived in the seat of Aston. Campbell lived in the inner-city suburb of Brunswick. She rented a property in the electorate and had promised to move to the electorate if elected. Doyle lived in the suburb of Mitcham, located in the nearby Deakin electorate.

The Australian Greens selected environmental engineer Angelica Di Camillo who had stood for the Greens in Rowville for the 2022 Victorian state election. She grew up in Rowville and was one of several Greens candidates under 30 years old at the federal election.

Key dates
Key dates in relation to the by-election are:
 * 27 February 2023 – Issue of writ
 * 6 March 2023 – Close of electoral rolls
 * 9 March 2023 – Close of nominations
 * 10 March 2023 – Declaration of nominations
 * 20 March 2023 – Start of early voting
 * 29 March 2023 – Postal vote applications close
 * 1 April 2023 – Polling day (8am to 6pm)
 * 6 April 2023 – Declaration of result
 * 14 April 2023 – Last day for receipt of postal votes
 * 7 June 2023 – Last day for return of writs

Candidates
One Nation chose not to contest the by-election, with party leader Pauline Hanson stating she had made a "strategic decision not to take votes away from the Coalition".

Simon Holmes à Court, founder of Climate 200, had expressed interest in funding a community-based teal independent if one were to run.

The Conservative Party, an unregistered party, endorsed volunteer community radio presenter Mark Gardner as a candidate but he did not end up contesting.

Campaign
The Liberal Party campaigned on the rising cost of living and the withdrawal of funding to local road and transport projects under the new Albanese Labor government. These projects included the Dorset Road extension, Wellington Road duplication, Napoleon Road duplication and the proposed Rowville railway line (also known as Monash Rail).

Labor campaigned on Liberal leader Peter Dutton's unpopularity, and the unpopularity of the Liberal Party generally. Labor also highlighted Dutton's rhetoric against China in messaging to Chinese Australians. The Labor Party also highlighted the fact that Campbell did not live in the outer eastern suburbs of Melbourne where the seat is located.

A week before the election, the state Liberal Party attracted controversy when one of its state MPs, Moira Deeming, attended an anti-transgender protest which was also attended by neo-Nazis. The parliamentary leader of the state Liberal Party, John Pesutto, moved to expel Deeming from the party, but later withdrew the motion due to internal opposition. Dutton was concerned that these events from the state party could impact the party's results at the by-election.