<P> The Canadian prime minister serves at Her Majesty's pleasure, meaning the post does not have a fixed term . Once appointed and sworn in by the governor general, the prime minister remains in office until he or she resigns, is dismissed, or dies . The lifespan of parliament was limited by the constitution to five years and, though the governor general may still, on the advice of the prime minister, dissolve parliament and issue the writs of election prior to the date mandated by the Canada Elections Act; the King--Byng Affair was the only time since Confederation that the governor general deemed it necessary to refuse his prime minister's request for a general vote . As of 2007, with an amendment to the Elections Act, Section 56.1 (2) was changed to limit the term of a majority government to four years, with election day being set as the third Monday in October of the fourth calendar year after the previous polling date . </P> <P> Following parliamentary dissolution, the prime minister must run in the resulting general election if he or she wishes to maintain a seat in the House of Commons . Should the prime minister's party subsequently win a majority of seats in the House of Commons, it is unnecessary to re-appoint the prime minister or again swear him or her into office . If, however, an opposition party wins a majority of seats, the prime minister may resign or be dismissed by the governor general . Should the prime minister's party achieve a minority while an opposition party wins a plurality (i.e., more seats than any other party but less than a majority), the prime minister can attempt to maintain the confidence of the House by forming a coalition with other minority parties . This option was last entertained in 1925 . </P> <P> Because the prime minister is, in practice, the most politically powerful member of the Canadian government, he or she is sometimes erroneously referred to as Canada's head of state, when, in fact, that post is held by the Canadian monarch, represented by the governor general . The prime minister is, instead, the head of government and is responsible for advising the Crown on how to exercise the Royal Prerogative and its executive powers, which are governed by the constitution and its conventions . However, the function of the prime minister has evolved with increasing power . Today, as per the doctrines of constitutional monarchy, the advice given by the prime minister is ordinarily binding, meaning the prime minister effectively carries out those duties ascribed to the sovereign or governor general, leaving the latter to act in predominantly ceremonial fashions . As such, the prime minister, supported by the Office of the Prime Minister (PMO), controls the appointments of many key figures in Canada's system of governance, including the governor general, the Cabinet, justices of the Supreme Court, senators, heads of crown corporations, ambassadors to foreign countries, the provincial lieutenant governors, and approximately 3,100 other positions . Further, the prime minister plays a prominent role in the legislative process--with the majority of bills put before parliament originating in the Cabinet--and the leadership of the Canadian Armed Forces . </P> <P> Pierre Trudeau is credited with, throughout his tenure as prime minister between 1968 and 1984, consolidating power in the PMO, which is itself filled by political and administrative staff selected at the prime minister's discretion and unaccountable to parliament . At the end of the 20th century and into the 21st, analysts--such as Jeffrey Simpson, Donald Savoie, Andrew Coyne, and John Gomery--argued that both parliament and the Cabinet had become eclipsed by prime ministerial power; Savoie wrote: "The Canadian prime minister has little in the way of institutional check, at least inside government, to inhibit his ability to have his way ." Indeed, the position has been described as undergoing a "presidentialisation", to the point that its incumbents publicly outshine the actual head of state (and prime minister's spouses are sometimes called the "First Lady of Canada"). Former governor general Adrienne Clarkson alluded to what she saw as "an unspoken rivalry" that had developed between the prime minister and the Crown . It has been theorized that such is the case in Canada as its parliament is less influential on the executive than in other countries with Westminster parliamentary systems; particularly, Canada has fewer MPs, a higher turnover rate of MPs after each election, and an Americanised system for selecting political party leaders, leaving them accountable to the party membership rather than caucus, as is the case in the United Kingdom . </P>

What is the role of the prime minister in canada
find me the text answering this question