On 19 August, he announced that British authorities had confirmed that he is a British Overseas citizen, a lesser form of British nationality. He stated that he would not resign from the Parliament, but would await a High Court decision. On 6 October 2017, he announced his intention to resign from the Senate in order to stand for the Parliament of South Australia at the South Australian general election due in March 2018. The High Court heard submissions from 10 to 12 October 2017 from the Solicitor-General of Australia, Stephen Donaghue, legal representatives of the seven parliamentarians involved, Tony Windsor in the Joyce matter, and an "amicus curiae" appointed to assist the Court. On 27 October 2017, the High Court handed down its decision. In a unanimous judgment, the Court interpreted s 44(i) according to the "ordinary and natural meaning" of its language. On that approach, it first affirmed the view taken in "Sykes v Cleary" that the question of eligibility is to be determined with reference to the point of nomination. The Court then followed the reasoning of the majority in "Sykes v Cleary". The Court said in part (emphases added):  The Court ruled that the fact of citizenship was disqualifying, regardless of whether the person knew of the citizenship or engaged in any voluntary act of acquisition. It emphasised that to hold otherwise would introduce an element of subjectivity that "would be inimical to the stability of representative government". It followed that each of Joyce, Ludlam, Nash, Roberts and Waters had been ineligible to be elected. However, Canavan and Xenophon had been eligible. It was determined that Canavan, under Italian law, was not a citizen of Italy. It was found that Xenophon was a British Overseas citizen, but that this did not give him the right to enter or reside in the United Kingdom; therefore, for the purposes of s 44(i), he was neither a citizen nor entitled to the rights and privileges of a citizen of the United Kingdom. The Court declared the seats of the ineligible members to be vacant, It ordered that the vacancy in the House of Representatives be filled through a by-election and that the vacancies in the Senate be filled by "special counts" (i.e., countbacks) of the ballot papers in each State, subject to supervision by a Justice of the Court. At an earlier directions hearing, the Chief Justice had approved the Commonwealth's undertaking to pay the legal costs of the all the parties and of Tony Windsor (intervening in the Joyce case).