The Succession to the Throne Act, 2013 (), gave Canada's assent to the United Kingdom's 2013 changes to the rules of succession to the British throne. It was passed by the Parliament of Canada as Bill C-53, and received royal assent on 27 March 2013. The act was brought into force by the Governor-General-in-Council on 26 March 2015.

There was disagreement over the act's constitutionality and effectiveness in altering the line of succession to the Canadian throne. A challenge in Ontario Superior Court (Teskey v. Canada (Attorney General)) argued the law was unconstitutional, but it was dismissed at the Superior Court in 2013, and unsuccessfully appealed in 2014. Another challenge was filed in the Superior Court of Quebec (), but in 2016 the Superior Court dismissed the application, leaving the act in place. The Quebec Court of Appeal upheld that ruling in 2019. In 2020, the Supreme Court of Canada dismissed an application for leave to appeal, leaving the Court of Appeal decision standing.

Background

After questions from the media were prompted in April 2011 by the introduction to the British Parliament of a private member's bill seeking to change British royal succession from male-preference to absolute, Prime Minister Stephen Harper was criticized for his ambivalence toward amendment of the line of succession in Canada, being contrasted with Prime Minister of New Zealand John Key and Deputy Prime Minister of the United Kingdom Nick Clegg. Harper stated: "The successor to the throne is a man. The next successor to the throne is a man ... I don't think Canadians want to open a debate on the monarchy or constitutional matters at this time. That's our position. I just don't see that as a priority for Canadians right now at all."

On 28 October 2011, at the Commonwealth Heads of Government Meeting held in Perth, Western Australia, the heads of government of the 16 Commonwealth realms announced that they would introduce legislation to end the primacy of males over females and the disqualification of persons married to Catholic spouses in the succession to the Crown. In a letter to the other realms' heads of government, prior to the Perth Agreement, British Prime Minister David Cameron additionally proposed to limit the requirement to obtain the monarch's permission to marry to the first six people in line to the throne.

Harper stated in October 2011 that, "at some point, we will table legislation in the House of Commons and it would be my hope that that would be approved quickly." In an email to Postmedia News in December 2012, a spokesperson for the Prime Minister stated that the Canadian government was waiting for the British government to reveal its proposed legislation before "enact[ing] these changes in coordination with our realm partners". At the same time, a spokesperson for the New Democratic Party (the official opposition in the 41st Parliament) explained the party was in favour of the reforms. A spokesperson for the federal minister of justice stated a constitutional amendment was not required and the minister intended to present the proposed legislation to Parliament without obtaining the consent of the provinces.

Bill C-53 Content of the bill The content of the act is identical to Bill C-53, which was passed unamended. From its inception as a bill the long title has been An Act to Assent to Alterations in the Law Touching the Succession to the Throne and the short title has been the Succession to the Throne Act, 2013. As a bill, it consisted of a long preamble and three short provisions. The preamble outlined the monarch's powers as prescribed by the Constitution Act, 1867, followed by a summary of the Perth Agreement and the quoted preamble of Statute of Westminster, 1931, which expressed the convention that an alteration of the succession rules be assented to by the respective parliaments of all Commonwealth realms. It ended with the acknowledgement of the introduction of the Succession to the Crown Bill 2012 in the Parliament of the United Kingdom. Clause 1 provided the short title; clause 2 stated that the alteration in the law touching the succession to the throne set out in the Succession to the Crown Bill 2012, as laid before the British Parliament "is assented to"; and clause 3 allowed the Governor General-in-Council to determine the effective date.

The wording of clause 2 of the bill was nearly identical to the similar section in the Succession to the Throne Act, 1937, passed by the Parliament of Canada to legislatively ratify the Canadian Cabinet's earlier consent to the taking into the laws of Canada of His Majesty's Declaration of Abdication Act 1936, the act of the British Parliament that effected the abdication of Edward VIII as king of Canada, the United Kingdom, and the other Dominions. The Succession to the Throne Act, 1937, stated, "the alteration in the law touching the succession to the throne set forth in the act of the Parliament of the United Kingdom intituled 'His Majesty's Declaration of Abdication Act, 1936' is hereby assented to." The Succession to the Throne Act, 1937, however, also included His Majesty's Declaration of Abdication Act 1936 in a schedule, something the Succession to the Throne Act, 2013, does not do with the Succession to the Crown Bill 2012.

In the House of Commons

Bill C-53 was, along with English- and French-language versions of the Succession to the Crown Bill 2012, tabled in the House of Commons by Justice Minister Rob Nicholson on 31 January 2013 and given first reading. At the time, Nicholson stated to the House that the Governor General had "given his consent as far as Her Majesty's prerogatives may be affected to the consideration by Parliament of the bill..." On 4 February 2013, the bill passed the House of Commons without debate and moved to the Senate.

In the Senate

Before the bill was put before the upper chamber, Senators Elaine McCoy, Serge Joyal, and Hugh Segal were all quoted in Maclean's as desiring a debate in the Senate on Bill C-53. McCoy stated her opinion that the bill was meaningless, as a law passed after 1982 by Britain's Parliament cannot have any effect in Canada,Section 2, while Segal expressed his support for the bill and the government's rationale behind it. All agreed a constitutional amendment would not be required.

On 5 February, the bill received its first reading in the Senate and the Succession to the Crown Bill 2012–13 was tabled. The bill's second reading in the Senate took place on 7 March 2013 and it was referred to the Standing Senate Committee on Legal and Constitutional Affairs. There, on 20 and 21 March, the committee heard from Associate Professor Andrew Heard of Simon Fraser University; Professor of Law Benoît Pelletier, from the University of Ottawa; Vice-Chairman Paul Benoit and Executive Director Garry Toffoli of the Canadian Royal Heritage Trust; Rob Nicholson; Karen Audcent, Donald Piragoff, and Warren Newman from the Department of Justice; and Joe Wild, Assistant Secretary to the Cabinet. The bill was returned to the Senate from the committee on 21 March 2013, unamended.

Third reading in the Senate, royal assent, and commencement In debate during the third reading, on 25 and 26 March, Senator Joan Fraser said that the Canadian Parliament was being asked to assent to a bill passed by a foreign parliament, the final form of which had not yet been seen, and that the Canadian bill was to give assent to the bill "laid before" the Parliament at Westminster, which had been amended since first presented there. Fraser commented that when the Senate had given the bill third reading, she would take that as formal notification that assent was being given to the bill eventually passed in Westminster, but it would have been preferable if Canada had done as Australia and New Zealand were doing: instead of passing a bill to assent to another parliament's legislation, they were passing their own, standalone legislation, thereby asserting that the monarch of each country is whomever each country's laws determines it to be.

Senator Serge Joyal responded by saying that Bill C-53 assented to the British bill by its title, not all its clauses. He argued that the legal force of a bill is essentially a legislative intention, to which some precision can be given, as had been done through the amendments made to the Succession to the Crown Bill 2012 by the British Parliament. The original intention approved by all of the 16 prime ministers of the Commonwealth realms had not been altered, but instead made more precise.

At the cessation of debate, the bill passed unamended and received royal assent the next day. The act was brought into force by order-in-council by the Governor General on 26 March 2015, the same day as the other Commonwealth realms that required their own legislation.

Constitutional issues

Cabinet position The government's stated position in 2013 was that "The changes to the laws of succession do not require a constitutional amendment. The laws governing succession are UK law and are not part of Canada's constitution. Specifically, they are not enumerated in the schedule to our Constitution Act, 1982, as part of the constitution of Canada. Furthermore, the changes to the laws of succession do not constitute a change to the 'office of The Queen', as contemplated in the Constitution Act, 1982. The office of the Queen includes the sovereign's constitutional status, powers, and rights in Canada. Neither the ban on the marriages of heirs to Roman Catholics, nor the common law governing male preference primogeniture, can properly be said to be royal powers or prerogatives in Canada. As the line of succession is therefore determined by UK law and not by the sovereign, the Queen's powers and rights have not been altered by the changes to the laws governing succession in Canada."

Judicial precedent

The Supreme Court of Canada declared unanimously in the 1981 Patriation Reference that the Bill of Rights, 1689, a law requiring amendment to implement the desired changes to royal succession, is "undoubtedly in force as part of the law of Canada". Furthermore, in O'Donohue v. Canada (2003) the Ontario Superior Court of Justice found that the Act of Settlement, 1701, is "part of the laws of Canada" and the rules of succession are "by necessity incorporated into the constitution of Canada". Another ruling of the Ontario Superior Court, in 2014, echoed the 2003 case, stating that the Act of Settlement "is an imperial statute which ultimately became part of the law of Canada." Upon dismissing appeal of that case, the Court of Appeal of Ontario stated "[t]he rules of succession are a part of the fabric of the constitution of Canada and incorporated into it".

Under section 41 of the Constitution Act, 1982, changes to the office of the monarch require unanimous consent of all the provinces and the federal Parliament. If changes to the line of succession to the Canadian throne were found to fall under this provision, it is possible that any single provincial legislature could hinder attempts at change. In the aforementioned court decision, Justice J. Rouleau determined that "unilateral changes by Canada to the rules of succession" would be "a fundamental change in the office of the Queen" requiring authorizations pursuant to section 41 of the Constitution Act, 1982. The precedent in question does not specify whether non-unilateral alterations to the rules of succession would also be considered a fundamental change in the office of Queen, requiring a constitutional amendment under the unanimous consent procedure. The judge stated that "a constitutional monarchy, where the monarch is shared with the United Kingdom and other Commonwealth countries, is, in [his] view, at the root of [Canada's] constitutional structure".

Provincial input