"proposed laws" were to be the subject of a future joint sitting. The joint sitting took place on 6–7 August 1974, and it passed the 6 trigger bills. Thirteen months later, four states challenged the validity of various laws passed in the joints sitting. The High Court upheld the validity of the Senate (Representation of Territories) Act 1973, the Commonwealth Electoral Act (No. 2) 1973, and the Representation Act 1973, The Petroleum and Minerals Authority Act 1973, was challenged on the grounds that there had not been the required 3 month gap between the Senate's first and second rejections of that Act. The High Court ruled that the Act was not eligible for the double dissolution process, as the Senate had not had sufficient time to "fail to pass" it. In 1975, the Whitlam government was again frustrated by a hostile Senate. The government had accumulated a total of 21 trigger bills, but did not call for a double dissolution. However, the Whitlam government was unable to obtain passage of appropriation bills through the hostile Senate, leading to the 1975 Australian constitutional crisis. On 11 November 1975, in an attempt to break the deadlock, Whitlam intended to call a half-Senate election, but instead was dismissed by the Governor-General, Sir John Kerr, who then appointed Malcolm Fraser, the Leader of the Liberal-Country coalition Opposition, caretaker Prime Minister. The Fraser minority government immediately passed the Supply bills through the Senate before losing a no-confidence motion in the House of Representatives. Kerr then dissolved both houses of Parliament on the advice of the new Prime Minister citing the trigger bills, even though Fraser had opposed the bills. Fraser remained the caretaker Prime Minister during the election campaign. In the election on 13 December 1975 the Fraser government was elected with a majority in both houses and the trigger bills were not brought up after the election. On 3 February 1983, Malcolm Fraser called a double dissolution, citing 13 trigger bills. When Fraser called the election, he expected he would be facing Bill Hayden as the alternative prime minister. But unbeknown to Fraser, Labor had changed leadership from Hayden to Bob Hawke earlier that same morning. The Fraser coalition government was defeated by the Labor Opposition led by Hawke at the election on 5 March 1983, and the bills lapsed. Fraser is the only prime minister to have advised two double dissolutions (1975 and