However, uncodified conventions, practices, and precedents continue to play a significant role in most countries, as many constitutions do not specify important elements of procedure. For example, some older constitutions using the Westminster system do not mention the existence of the cabinet or the prime minister, because these offices were taken for granted by the authors of these constitutions. Sometimes these conventions, reserve powers, and other influences collide in times of crisis and in such times the weaknesses of the unwritten aspects of the Westminster system, as well as the strengths of the Westminster system's flexibility, are put to the test. As an illustrative example, in the Australian constitutional crisis of 1975 the Governor-General of Australia, Sir John Kerr, dismissed Prime Minister Gough Whitlam and replaced him with opposition leader Malcolm Fraser.