was not validly occupying ministerial office would themselves be invalid. While Matthew Canavan had already resigned from his positions of Minister for Resources and Northern Australia in the Cabinet prior to Labor's proposition, the other two Cabinet ministers, Barnaby Joyce and Fiona Nash, chose to remain in their positions until the court handed down its decision. According to some legal opinion, more than 100 Turnbull government decisions are vulnerable to legal challenge as a result of Joyce and Nash's ineligibility, with lawyers concluding there is a high likelihood the work the pair has done over the last year will end up before the courts. Post-Re Canavan resignations and referrals After the decision in Re Canavan was handed down, several other parliamentarians discovered that they held dual citizenship and resigned. Liberal Senator and President of the Senate Stephen Parry, Liberal MP John Alexander, Jacqui Lambie Network Senator Jacqui Lambie, and NXT Senator Skye Kakoschke-Moore each resigned after individually discovering that they held British citizenship by descent. The Senate referred all three Senate cases to the High Court as the Court of Disputed Returns. A by-election in Alexander's seat was held on 16 December; Alexander was a candidate, having renounced his foreign citizenship, and retained the seat. On 6 December the House of Representatives referred Labor MP David Feeney to the High Court as the Court of Disputed Returns and the Senate referred Labor Senator Katy Gallagher. Feeney stated in the citizenship register that his father was born in Northern Ireland, and that he was advised by the party to ensure he renounced British (and potentially Irish) citizenship before nominating. Feeney said he did so in late 2007, but was unable to produce documentation confirming the renunciation had been registered. His legal representative submitted that Feeney's renunciation was lodged, but was not registered by British authorities "[f]or some reason". On 1 February 2018, before any further court proceedings, Feeney announced his resignation from the House of Representatives, and confirmed that he had been unable to find documentation proving his renunciation of British citizenship. On 23 February 2018, the Court held that Fenney had been ineligible to be elected by virtue of s.44(i) and that the vacancy is to be filled by a by-election. Feeney did not re-contest the seat in the by-election. Gallagher filed UK citizenship renunciation papers with the UK Home Office on 20 April 2016, in the lead-up to the