Amid the 2017–18 Australian parliamentary eligibility crisis, the trigger for the by-election was the resignation of Liberal incumbent John Alexander effective 11 November 2017. A few weeks following the increased clarity which came from the judgment of the High Court of Australia sitting as the Court of Disputed Returns on 27 October 2017 further determining dual citizenship ineligibility under Section 44 of the Constitution, Alexander resigned due to a belief that he may have held British citizenship at the time of his nomination and election, meaning he would be ineligible under Section 44 of the Constitution to sit in the Parliament of Australia. Alexander renounced any British citizenship he may have held, or otherwise been eligible for, in order to nominate for election again.