On 30 June 1975, Bertie Milliner, a Queensland ALP Senator, died suddenly. It had long been a tradition that when a casual vacancy occurred in the Senate, the relevant political party would nominate the replacement to the state premier, and the state parliament would formally appoint that person as the new senator. Following the usual practice, the Labor Party nominated only one person, Mal Colston, to replace Milliner. Country Party Premier Joh Bjelke-Petersen asked for a list of three names from which he would choose the replacement; he was possibly relying on a 1962 precedent, when his predecessor, Frank Nicklin, had also required such a list of names. The Labor Party refused to provide a list and insisted on Colston being appointed.