the party membership rather than caucus (as is the case in the UK). There do exist checks on the prime minister's power: the House of 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 Senate, 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 sovereign's supremacy over the prime minister in the constitutional order is thus seen as a "rebuff to the pretensions of the elected: As it has been said, when the prime minister bows before the queen, he bows before us [the Canadian people]." Either the sovereign or his or her governor general may therefore oppose the prime minister's will in extreme, crisis situations. Near the end of her time as governor general, Adrienne Clarkson stated: "My constitutional role has lain in what are called 'reserve powers': making sure that there is a prime minister and a government in place, and exercising the right 'to encourage, to advise, and to warn'[...] Without really revealing any secrets, I can tell you that I have done all three." Privileges Two official residences are provided to the prime minister—24 Sussex Drive in Ottawa and Harrington Lake, a country retreat in Gatineau Park—as well an office in the Office of the Prime Minister and Privy Council building (formerly known as Langevin Block), across from Parliament Hill. For transportation, the prime minister is afforded an armoured car (a car allowance of $2,000 per year) and shared use of two official