Although it did not become a constitutional requirement until 1977, it had been long-standing convention that a Senate casual vacancy be filled by a person from the same political party. However, on 27 February 1975, the Premier of New South Wales, Tom Lewis, controversially appointed Cleaver Bunton, a person with no political affiliations, to replace Murphy in the Senate, beginning the chain of events which led to the 1975 Australian constitutional crisis. These events provided the impetus for the 1977 constitutional change that ensures such an appointment cannot be repeated, although a State Government can still achieve a similar result by declining to fill a Senate vacancy. Soon after his appointment to the bench, Murphy visited Justice Menzies' old chambers in Taylor Square, which would now be his. Staring at the volumes of British law reports on the shelves behind his desk, he said, "I want all of these to go". He replaced them with decisions from the Supreme Court of the United States.