Due to the High Court ruling against Senator Katy Gallagher on 9 May 2018 as part of the ongoing parliamentary eligibility crisis, Lamb and three other MPs in the same situation announced their parliamentary resignations later that day, while the Perth incumbent resigned for family reasons. The Speaker announced on 24 May 2018 that he had scheduled the by-elections to occur on 28 July 2018. Popularly labelled "Super Saturday", the occurrence of five simultaneous federal by-elections is unprecedented in Australian political history. The others are: