Before 1982, modifying the Constitution of Canada primarily meant amending the British North America Act, 1867. Unlike most other constitutions, however, the Act had no amending formula; instead, changes were enacted through Acts of the Parliament of the United Kingdom (or "Imperial Parliament") called the British North America Acts.
Other Commonwealth countries had taken over the authority for constitutional amendment after the Statute of Westminster 1931, but at the time, Canada decided to allow the Parliament of the United Kingdom to retain the power "temporarily". Between 1931 and 1982, the federal government, on behalf of the House of Commons of Canada and the Senate, would issue an address to the British government requesting an amendment. The request would include a resolution containing the desired amendments, which in turn were always passed by the British Parliament with little or no debate.
With the Constitution Act, 1982, Canada took over the authority to amend its own constitution, achieving full sovereignty. Since then, amendments to the Constitution of Canada have been made using one of five amending formulas requiring consent of some combination of the House of Commons, Senate, and provincial legislatures.
Amendment formulas
As part of the patriation of the constitution in 1982 an amending formula was adopted in sections 38 to 49 of the Constitution Act, 1982.
According to this act, the amendment procedure is composed of different categories, depending on the part of the constitution to be amended.
Unanimous consent amendments There are some parts of the constitution that can be modified only with the unanimous consent of all the provincial legislative assemblies plus the two Houses of Parliament. This does not affect the actual passing of the resolutions granting consent in each legislative chamber, which as usual requires a simple majority in that chamber - it is the final resolutions that must be unanimous. This formula is contained in section 41 of the Constitution Act, 1982, and is known as the "unanimity formula". It is reserved for the following matters:
"7/50 formula" amendments For some constitutional provisions, amendments can be passed only if identical resolutions are adopted by the House of Commons, the Senate and two-thirds or more of the provincial legislative assemblies (i.e. at least seven) representing at least 50 per cent of the total population of the provinces. This formula, which is outlined in section 38 of the Constitution Act, 1982, is officially referred to as the "general amendment procedure" and is known colloquially as the "7/50 formula". It is the amendment formula that applies when the amendment does not fall into any other category.
Once the procedure for the adoption of the amendment is followed successfully, the amendment is formalized as a proclamation of the Governor General in Council. Officially, therefore, the constitution is amended by Proclamation, and the issue of the Proclamation requires prior approval by resolutions of the House of Commons, the Senate, and the necessary number of provincial legislative assemblies.
The following matters are explicitly reserved to the "7/50 formula", by virtue of s. 42:
No specific mention is made in the procedure for amendments affecting what falls within the federal/provincial distribution of powers. Therefore, they can be dealt with generally under s. 38, or with respect to specific provinces under s. 43. However, a s. 38 amendment in that regard will not apply to a province that has passed a resolution of dissent from it, and s. 40 states that a s. 38 amendment that transfers provincial jurisdiction over an education or cultural matter to Parliament must be accompanied by reasonable compensation by Canada to the provinces.
Provisions applying to one or more, but not all, provinces According to s. 43, any amendment applying to one or more, but not all, provinces must be "authorized by resolution of the Senate and House of Commons and of the legislative assembly of each province to which the amendment applies."
If a constitutional amendment affects only one province, only the assent of the two houses of Parliament and of that province's legislative assembly is required. Eight of the thirteen amendments passed since 1982 have been of this nature, four being passed by and for Newfoundland and Labrador, one for New Brunswick, one for Prince Edward Island, one for Quebec, and one for Saskatchewan. This formula is contained in section 43 of the Constitution Act, 1982.
Provisions concerning federal institutions According to s. 44, constitutional provisions concerning federal institutions (executive government of Canada, Senate, and House of Commons) can be amended unilaterally by the Parliament of Canada if the provisions are not those explicitly reserved for unanimity or 7/50 formula. For example, in 2022, the Canadian government used this amendment method to modify the House of Commons seat allocation formula.
Provincial constitutions According to s. 45, each province has the exclusive power to modify its own constitution, if the changes do not concern matters outlined in s. 41. This section has been the subject of much confusion and debate, since some provincial constitutions are embedded in the same documents that form the Constitution of Canada.
Bypassing the Senate Section 47 allows an amendment to the Constitution of Canada to be made without a resolution of the Senate authorizing the issue of the proclamation if, within 180 days after the adoption by the House of Commons of a resolution authorizing its issue, the Senate has not adopted such a resolution and if, at any time after the expiration of that period, the House of Commons again adopts the resolution. Any period when Parliament is prorogued or dissolved shall not be counted in computing the 180-day period. Section 47 only applies to amendments made under the Section 38(1) Amendment by General Procedure, the Section 41 Amendment by Unanimous Consent, Section 42 and the Section 43 Amendment by Bilateral Agreement procedures
Amendments before 1982 A majority of the constitutional amendments before 1982 were acts of the United Kingdom or Canadian parliaments to amend the British North America Act, 1867 (now the Constitution Act, 1867). In some cases, amendments were made to the constitutional structure of Canada by adding entire extra documents to the constitution. These include orders that added provinces to Canada, such as the British Columbia Terms of Union and documents that altered the structure of the government of Canada, such as the Parliament of Canada Act, 1875.
+ List of Constitutional amendments from 1867 to 1982NameYearAmendments to other constitutional documentsStatus (as of 2022)Rupert's Land Act 18681868noneSpent when Rupert's Land and North-Western Territory Order came into effect.Temporary Government of Rupert's Land Act, 18691869noneExpired on 14 April 1871.An Act to amend and continue the Act 32–33 Victoria chapter 3; and to establish and provide for the Government of the Province of Manitoba, 18701870Section 21 of the Constitution Act, 1867In the Constitution under the name Manitoba Act, 1870.Order of Her Majesty in Council admitting Rupert's Land and the North-Western Territory into the Union, dated the 23rd day of June, 18701870noneIn the constitution under the name Rupert's Land and North-Western Territory Order.Order of Her Majesty in Council admitting British Columbia into the Union, dated the 16th day of May, 1871.1871Section 21 of the Constitution Act, 1867In the constitution under the name British Columbia Terms of Union.British North America Act, 18711871noneIn the constitution under the name Constitution Act, 1871.Order of Her Majesty in Council admitting Prince Edward Island into the Union, dated the 26th day of June, 1873.1873noneIn the Constitution under the name Prince Edward Island Terms of Union.Parliament of Canada Act, 18751875Section 18 of the Constitution Act, 1867In the constitution under the same name.Order of Her Majesty in Council admitting all British possessions and Territories in North America and islands adjacent thereto into the Union, dated the 31st day of July, 1880.1880noneIn the constitution under the name Adjacent Territories Order.British North America Act, 18861886noneIn the constitution under the name Constitution Act, 1886.Canada (Ontario Boundary) Act, 18891889noneIn the constitution under the same name.Statute Law Revision Act, 18931893Enacting clause and sections 2, 4, 25, 42, 43, 51, 81, 88, 89, 127, 145 of the Constitution Act, 1867British North America Act and Amendments . . . 1867–1943. King's Printer. 1943. p. 78 (see further p. 76).Spent.Canadian Speaker (Appointment of Deputy) Act, 18951895noneRepealed in 1982.The Alberta Act, 19051905Section 21 of the Constitution Act, 1867In the constitution under the name Alberta Act.The Saskatchewan Act, 19051905Section 21 of the Constitution Act, 1867In the constitution under the name Saskatchewan Act.British North America Act, 19071907noneIn the constitution under the name Constitution Act, 1907.British North America Act, 19151915Sections 21, 22, 26, 27, 28, 51A of the Constitution Act, 1867In the constitution under the name Constitution Act, 1915.British North America Act, 19161916noneRepealed by Statute Law Revision Act, 1927.Statute Law Revision Act, 19271927Removed section 1(2) from the British North America Act, 1915 and repealed British North America Act, 1916.Spent.British North America Act, 19301930noneIn the constitution under the name Constitution Act, 1930.Statute of Westminster, 19311931noneIn the constitution under the same name.British North America Act, 19401940Section 91(2A) of the Constitution Act, 1867In the constitution under the name Constitution Act, 1940.British North America Act, 19431943Section 51 of the Constitution Act, 1867Repealed in 1982.British North America Act, 19461946Section 51 of the Constitution Act, 1867Repealed in 1982.British North America Act, 19491949Section 21, 22 of the Constitution Act, 1867In the Constitution under the name Newfoundland Act.British North America (No. 2) Act, 19491949Section 91 of the Constitution Act, 1867Repealed in 1982.Statute Law Revision Act, 19501950Removed the redundant section 118 of the Constitution Act, 1867.Spent.British North America Act, 19511951Section 94A of the Constitution Act, 1867Repealed in 1982.British North America Act, 19521952Section 51 of the Constitution Act, 1867Repealed in 1982.British North America Act, 19601960Section 99 of the Constitution Act, 1867In the constitution under the name Constitution Act, 1960.British North America Act, 19641964Section 94(A) of the Constitution Act, 1867In the constitution under the name Constitution Act, 1964.British North America Act, 19651965Section 29 of the Constitution Act, 1867In the constitution under the name Constitution Act, 1965.British North America Act, 19741974Section 51(1) of the Constitution Act, 1867In the constitution under the name Constitution Act, 1974.British North America Act (No. 1), 1975 (previously named Northwest Territories Representation Act)1975Section 51(2) of the Constitution Act, 1867Repealed in 1999 after being renamed Constitution Act (No. 1), 1975.British North America Act (No. 2), 19751975Sections 21, 22, 28 of the Constitution Act, 1867In the constitution under the name Constitution Act (No. 2), 1975.Miscellaneous Statute Law Revision Act, 19771977Renamed constitutional documents that were, again renamed by the Constitution Act, 1982.Spent.Canada Act 19821982noneIn the constitution under the same name.Constitution Act, 19821982Sections 1, 20, 51, 91(1), 92(1), 92A(6), 94A, Sixth Schedule of the Constitution Act, 1867In the constitution under the same name.
Amendments after 1982