History rightly records Marilyn Waring's role as the critical vote in Caucus, with Mr Minogue's passing he is being appropriately recognised too.
Update: I've been a little frustrated at being unable to verify whether or not Mike Minogue crossed the floor to support Prebble's anti-nuclear bill in 1983. NZ's online Hansard records don't go back beyond 2000.
I've checked the half dozen books I have on this period in NZ's political history (sadly I don't have Gustafson's various publications) but haven't found anything definitive and have had to resort to Google. Fortunately, Google turned up this source (Masters thesis from Otago University Doctoral student, Andreas Rietzig) which includes the following paragraph confirming that Minogue did in fact cross the floor (thanks also to Poneke for his piece on Minogue which also said he'd crossed the floor).
The following year, Richard Prebble launched his third attempt to make New Zealand nuclear-free. On 12 June 1984, Prebble introduced the Nuclear Free New Zealand Bill. This time, also Prebble’s bill called for the exclusion of nuclear-powered ships from New Zealand. As Prebble explained, the bill ‘prohibits the entry of nuclear powered ships and nuclear weapons into New Zealand and further prohibits the building of nuclear reactors within New Zealand.’ Prebble almost succeeded to introduce this bill because National Party MP Marilyn Waring threatened Prime Minister Muldoon to cross the floor and vote for Prebble’s bill against her own party caucus.
As a result, National Party MPs prevented Waring from speaking in Parliament that day by raising numerous points of order until Waring’s time to speak had expired. On the following day, Prebble’s bill was defeated by 40 to 39 votes just like Beetham’s bill one year earlier. Nevertheless, Waring did vote for the bill together with her colleague Mike Minogue. Prebble’s bill was only defeated because two alienated Labour MPs had voted with the government. Since National had a majority of only one person in Parliament, Waring’s decision seriously called Muldoon’s leadership into question. Consequently, Muldoon announced on 14 June 1984 that he would call a snap election because he could no longer rely on Marilyn Waring’s support and could not govern effectively anymore.