Because the prime minister is, in practice, the most politically powerful member of the Canadian government, they are 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.

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 Americanized system for selecting political party leaders, leaving them accountable to the party membership rather than caucus, as is the case in the United Kingdom.

There do exist checks on the prime minister's power: the Commons may revoke its confidence in an incumbent prime minister and Cabinet or caucus revolts can quickly bring down a serving premier and even mere threats of such action can persuade or compel a prime minister to resign his post, as happened with Jean Chrétien.
The Reform Act, 2014, codifies the process by which a caucus may trigger a party leadership review and, if necessary, chose an interim leader, thereby making a prime minister more accountable to the MPs in his or her party.
Caucuses may choose to follow these rules, though the decision would be made by recorded vote, thereby subjecting the party's choice to public scrutiny.

The Senate may delay or impede legislation put forward by the Cabinet, such as when Brian Mulroney's bill creating the Goods and Services Tax (GST) came before the upper chamber and, given Canada's federal nature, the jurisdiction of the federal government is limited to areas prescribed by the constitution.
Further, as executive power is constitutionally vested in the monarch, meaning the Royal Prerogative belongs to the Crown and not to any of its ministers, the so
Because the prime minister is, in practice, the most politically powerful member of the Canadian government, they are 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.
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 Americanized system for selecting political party leaders, leaving them accountable to the party membership rather than caucus, as is the case in the United Kingdom.
There do exist checks on the prime minister's power: the Commons may revoke its confidence in an incumbent prime minister and Cabinet or caucus revolts can quickly bring down a serving premier and even mere threats of such action can persuade or compel a prime minister to resign his post, as happened with Jean Chrétien. The Reform Act, 2014, codifies the process by which a caucus may trigger a party leadership review and, if necessary, chose an interim leader, thereby making a prime minister more accountable to the MPs in his or her party. Caucuses may choose to follow these rules, though the decision would be made by recorded vote, thereby subjecting the party's choice to public scrutiny.
The Senate may delay or impede legislation put forward by the Cabinet, such as when Brian Mulroney's bill creating the Goods and Services Tax (GST) came before the upper chamber and, given Canada's federal nature, the jurisdiction of the federal government is limited to areas prescribed by the constitution. Further, as executive power is constitutionally vested in the monarch, meaning the Royal Prerogative belongs to the Crown and not to any of its ministers, the so
Prime Minister of Canada