A constitutional amendment (or constitutional alteration) is a modification of the constitution of a polity, organization or other type of entity. Amendments are often interwoven into the relevant sections of an existing constitution, directly altering the text. Conversely, they can be appended to the constitution as supplemental additions (codicils), thus changing the frame of government without altering the existing text of the document.

Most constitutions require that amendments be enacted through a special procedure that is more stringent than the process for passing ordinary legislation. Examples of such special procedures include supermajorities in the legislature, or direct approval by the electorate in a referendum, or even a combination of two or more different special procedures. A referendum to amend the constitution may also be triggered in some jurisdictions by popular initiative.

Australia and Ireland provide examples of constitutions requiring that all amendments are first passed by the legislature before being submitted to the people; in the case of Ireland, a simple majority of those voting at the electorate is all that is required, whereas a more complex set of criteria must be met in Australia (a majority of voters in a majority of states is also necessary). Switzerland has procedure similar to that of Australia.

The special procedures for the amendment of some constitutions have proven to be so exacting, that of proposed amendments either few (eight Amendments out of 44 proposed in Australia), or none (as in Japan) have been passed over a period of several decades. In contrast, the former constitution of the U.S. state of Alabama was amended 977 times between its adoption in 1901 and its replacement by the current constitution in 2022.

Form of changes to the text

There are a number of formal differences, from one jurisdiction to another, in the manner in which constitutional amendments are both originally drafted and written down once they become law. In some jurisdictions, such as Ireland, Estonia, and Australia, constitutional amendments originate as bills and become laws in the form of acts of parliament. This may be the case notwithstanding the fact that a special procedure is required to bring an amendment into force. Thus, for example, in Ireland and Australia although amendments are drafted in the form of acts of Parliament they cannot become law until they have been approved in a referendum. By contrast, in the United States a proposed amendment originates as a special joint resolution of Congress that does not require the president to sign and that the president can not veto.

The manner in which constitutional amendments are finally recorded takes two main forms. In most jurisdictions, amendments to a constitution take the form of revisions to the previous text.[1] Thus, once an amendment has become law, portions of the original text may be deleted or new articles may be inserted among existing ones. The second, less common method, is for amendments to be appended to the end of the main text in the form of special articles of amendment, leaving the body of the original text intact. Although the wording of the original text is not altered, the doctrine of implied repeal applies. In other words, in the event of conflict, an article of amendment will usually take precedence over the provisions of the original text, or of an earlier amendment. Nonetheless, there may still be ambiguity whether an amendment is intended to supersede or to supplement an existing article in the text.

An article of amendment may, however, explicitly express itself as having the effect of repealing a specific existing article.[2] The use of appended articles of amendment is most famous as a feature of the United States Constitution, but it is also the method of amendment in a number of other jurisdictions, such as Venezuela.

Under the 1919 German Weimar Constitution, the prevailing legal theory was that any law reaching the necessary supermajorities in both chambers of parliament was free to deviate from the terms of the constitution, without itself becoming part of the constitution. This very wide conception of "amendment" eased the rise of Adolf Hitler to power; it was consequently explicitly ruled out in the postwar 1949 constitution, which allows amendments only by explicitly changing the constitution's text.

Summary of methods

Table of amendment procedures[3][4]
Constitution Proposed by Approval by Referendum requirement Majority or Supermajority Entrenched clauses?
Afghanistan President Legislature No 2/3 Yes
Albania Legislature (1/5) Legislature Yes 2/3 + >50% No
Algeria President Both houses of legislature + referendum (or Constitutional council + both houses of legislature) >50% (or 3/4) Yes
Andorra Monarch Legislature Yes 2/3 + >50% No
Legislature (1/3)
Angola President Legislature 2/3 Yes
Legislature (1/3)
Antigua and Barbuda Both houses of legislature Yes 2/3 (>50% in upper house) + 2/3 No
Argentina Legislature (2/3) Constitutional convention No 2/3 No
Armenia 1/3 of Parliament, the Government, or 200,000 voters for certain amendments; 1/4 of Parliament, the Government, or 150,000 voters for others. Additional 300,000 voters overrides need for Parliament. Legislature Sometimes 2/3 (+ >50%). Yes
Australia Legislature (1 member) Both houses of legislature (usually; see below) Yes >50% (absolute) in legislature + >50% (simple) nationally and in at least 4 of the 6 states and in any state where certain rights of that state are affected No
Austria Lower house (+ upper house in certain cases) Sometimes (fundamental changes) 2/3 + (2/3) No
Bahrain Legislature (15 members) Both houses of legislature (or joint session) Yes 2/3 (or 2/3) Yes
Bangladesh Legislature Yes 2/3 Yes
Belgium Legislature (either house) Legislature (before and after an election) No 2/3 Yes (during a regency)
Brazil President Both houses of legislature No 3/5 Yes
Legislature (1/3 of either house)
Sub-national legislature (>50%)
Bulgaria President Legislature (or constitutional convention for certain amendments) 3/4 or 2/3 in two sittings (2/3 for constitutional convention) No
Legislature (1/4) 2/3
Cambodia Monarch Legislature No 2/3 Yes
Prime Minister
Legislature (1/4)
Canada Both houses of legislature + 2/3 of provincial legislatures representing majority of population No >50% + >50% No
Chile Legislature or President Both houses of legislature No 4/7 No
China Legislature (Standing Committee) Legislature No 2/3 No
Legislature (1/5)
China, Republic of Legislature (1/4) Legislature Yes 3/4 + >50% of total electorate No
Czech Republic Both houses of legislature No 3/5 Yes
Denmark Legislature (before and after an election) Yes >50% + >50% (representing >40% of electorate) No
Djibouti President Legislature (or legislature + referendum) Yes 2/3 (or >50% + >50%) Yes
Legislature (1/3)
Ecuador President Legislature (or Legislature + referendum) 2/3 (or >50% + >50% Yes
Legislature (1/3)
Electorate (1%)
Estonia President Legislature with or without an election (or referendum) >50% + 3/5 after an election or 4/5 without an election (or >50%) No
Legislature (1/5)
Ethiopia Legislature (2/3 of either house) Legislature in joint session + sub-national legislatures (or each house of legislature + sub-national legislature for certain sections) 2/3 + 2/3 (or 2/3 + 100%) No
Sub-national legislatures (1/3)
Egypt President Lower house Yes 2/3 + >50% Yes
Legislature (1/5 of lower house)
Fiji Legislature Yes 3/4 + 3/4 Yes
Finland Government Legislature before and after an election (or a proposal can be declared by 5/6 as "urgent" and can then be passed without an election) No >50% + 2/3 (or 5/6 + 2/3) No
Legislature (1 member)
France President Both houses of legislature (or legislature in joint session) Yes >50% + >50% (or 3/5) No
Legislature (any legislator)
Gabon President Both houses of legislature + joint session (or referendum) Sometimes >50% + 2/3 (or >50%) Yes
Government
Legislature (1/3 of either house)
Germany Both houses of legislature 2/3 Yes
Greece Legislature (50 legislators) Legislature before and after an election 3/5 + >50% or >50% + 3/5 Yes
Haiti Executive Both houses of legislature + joint session after an election 2/3 + 2/3 Yes
Legislature (Either house)
Honduras Legislature 2/3 Yes
Hungary President Legislature 2/3 No
Government
Legislature (1/5)
Iceland Legislature before and after an election Sometimes

(referendum if on status of the Church)

>50% (+ >50%) No
India Both houses of legislature (+ sub-national legislatures in some cases) 2/3 (+ 50%) No
Indonesia Legislature (1/3) Joint session of legislature >50%+1 Yes
Ireland Both houses of legislature Yes >50% + >50% No
Italy Both houses of legislature (or both houses of legislature + referendum) Sometimes 2/3 (or >50% + >50%) Yes
Japan Legislature (2/3) Both houses of legislature Yes 2/3 + >50% No
Jordan Both houses of legislature 2/3 Yes
Kazakhstan President Both houses of legislature (or referendum) 3/4 + >50% representing voters in 2/3 of the oblasts, major cities and the capital. Yes
Korea, Democratic People's Republic of Legislature 2/3 No
Laos Legislature 2/3 No
Libya Legislature 2/3 No
Madagascar President Both houses of legislature Yes 3/4 + >50% Yes
Legislature (2/3)
Malawi Legislature (or referendum) 2/3 (or >50%) No
Mexico Legislature + sub-national legislatures 2/3 + >50% No
Namibia Both houses of legislature (or lower house + referendum) 2/3 (or 2/3 + 2/3) Yes
The Netherlands Legislature (lower house) Both houses of legislature (before and after election) 50% before election, 2/3 after No
North Macedonia President Legislature 2/3 No
Government
Legislature (30 legislators)
Electorate (150,000 citizens)
Pakistan Legislature (either house) Both houses of legislature 2/3 No
Palau Legislature (3/4 of both houses) Referendum Yes >50% in 3/4 of states No
Electorate (25%)
Palestine Legislature 2/3 No
Philippines Legislature (2/3) Either of legislature or referendum. Yes >50% No
Constitutional convention
Electorate (12% of voters representing at least 3% of every electoral district)
Poland President Both houses of legislature Certain amendments e.g. about human rights, rule of law, democracy, equality, national symbols, future constitution amendment rules, require a referendum, but only when requested by 1/5 of the lower house of the parliament or by the president (or by the upper house but the upper house approval is required in the standard way anyway)[5]. 2/3 in lower house and >50% in upper house No
Sejm (1/5)
Senate
Portugal Legislature (Any legislator) Legislature 2/3 Yes
Qatar Monarch Legislature 2/3 Yes
Legislature (1/3)
Romania President Both houses of legislature (or joint session) Yes 2/3 (or 3/4) + >50% Yes
Legislature (1/4 in either house)
Electorate (500,000 voters)
Russia President Sub-national legislatures (or, in some cases, legislature in joint session + constitutional convention or referendum) 2/3 (or 3/5 + 2/3 or >50%) No
Government
Legislature (1/5 in either house)
Sub-national legislatures
Samoa Legislature 2/3
Sao Tome and Principe Legislature (Any legislator) Legislature 2/3 Yes
Senegal President Legislature (or referendum) 3/5 (or >50%) Yes
Legislature
Serbia President Legislature Sometimes 2/3 (+ >50%) No
Government
Legislature (1/3)
Electorate (150,000 voters)
Seychelles Legislature + referendum Yes 2/3 + >60% No
Sierra Leone Legislature Sometimes 2/3 + 2/3 representing >50% of electorate No
Singapore Legislature 2/3 No
Slovakia Legislature 3/5 No
Slovenia Government Legislature Sometimes (referendum if demanded by 30 legislators) 2/3 (+ >50% out of >50% of electorate) No
Legislature (20 legislators)
Electorate (20,000 voters)
Solomon Islands Legislature 2/3 (3/4 in certain cases) No
Somalia Government Both houses of legislature 2/3 Yes
Government (members)
Legislature (Any legislator)
Electorate (40,000 citizens)
Spain Government Both houses of legislature Sometimes

(referendum if demanded by 10% of either house of legislature)

3/5 (or >50% of upper house + 2/3 of lower house) Yes
Legislature (Any legislator)
Sweden Legislature before and after an election Sometimes

(referendum if demanded by 1/3 of legislature)

>50% + >50% No
Tajikistan President Referendum Yes >50% Yes
Legislature (2/3)
Tunisia President Legislature Yes 2/3 + >50% Yes
Legislature (1/3)
Turkey Legislature (1/3) Legislature Yes 3/5 + >50% Yes
Turkmenistan Legislature (or referendum) 2/3 (or >50%) Yes
Tuvalu Legislature 2/3 No
Uganda Legislature Yes 2/3 + >50% No
Ukraine President Legislature before an election + after an election Sometimes >50% + 2/3 (+ >50%) Yes
Legislature (1/3)
United Arab Emirates Legislature Legislature 2/3 No
United Kingdom Legislature (Any legislator) Legislature No Majority votes in House of Commons and House of Lords (or Commons only if Parliament Act invoked) with the consent of the monarch (although they are constitutionally required to grant consent) No
United States Legislature (2/3 of both houses) State legislatures or ratification conventions No 3/4 Yes
Sub-national legislature (2/3)
Uzbekistan Both houses of legislature in joint session (or referendum) 2/3 (or >50%) No
Vanuatu Prime Minister Legislature 2/3 No
Legislature (Any legislator)
Venezuela President Legislature Yes >50% + >50% No
Legislature (39%)
Electorate (15% of voters)
Vietnam President Legislature 2/3 No
Legislature (Standing Committee)
Legislature (2/3)
Yemen Prime Minister Legislature Sometimes 2/3 (+ >50%) No
Legislature (1/3 of lower house)
Zambia Legislature Yes 2/3 + >50% of total electorate No
Zimbabwe Both houses of legislature Sometimes 2/3 (+ >50%) No

Africa

Ethiopia

The Constitution of Ethiopia can only be modified by a two-thirds majority of the country's regions, and a two-thirds majority of a joint session of the Federal Parliamentary Assembly in accordance with Article 105. The constitution's Chapter Three (describing both Human and democratic rights) and the constitution's Articles 104 and 105 are almost unamendable since they require the total consensus of the federal regional states and two-thirds of each house of Parliament. In Ethiopia's federal experience, each regional state is equal and has the right to veto amendments to the aforementioned articles.

South Africa

The Constitution of South Africa can be amended by an Act of Parliament, but special procedures and requirements apply to the passage of constitutional amendments. A bill amending the Constitution must be introduced in the National Assembly, and cannot contain any provisions other than constitutional amendments and directly related matters.[6]: § 74 

At least 30 days before a constitutional amendment bill is introduced in the National Assembly, the person or committee introducing the amendment must publish it for public comment, submit it to the provincial legislatures, and, if it does not have to be passed by the National Council of Provinces (NCOP), submit it to the NCOP for debate. When the bill is introduced, the comments received must be tabled in the National Assembly, and in the NCOP when appropriate.[6]: § 74 

All amendments must be passed by an absolute two-thirds supermajority in the National Assembly (the lower house); as the Assembly has 400 members this requires 267 members to vote for the amendment. Most amendments do not have to be considered by the NCOP (the upper house). Amendments of the Bill of Rights, and amendments affecting the role of the NCOP, the "boundaries, powers, functions or institutions" of the provinces or provisions "dealing specifically with provincial matters" must also be passed by the NCOP with a supermajority of at least six of the nine provinces. If an amendment affects a specific province, it must also be approved by the legislature of the province concerned. Section 1, which defines South Africa as "one, sovereign, democratic state" and lists its founding values, is a specially entrenched clause and can only be amended by an absolute three-quarters supermajority in the National Assembly and six of the provinces in the NCOP.[6]: § 74 

Once an Act is passed by the National Assembly, and by the NCOP if necessary, it must be signed and assented to by the President. As with any other Act of Parliament, by default an amendment comes into effect when it is published in the Government Gazette, but the text of the amendment may specify some other date of commencement, or allow the President to specify one by notice in the Gazette.[6]: § 81 

Americas

Brazil

The Constitution of Brazil states various terms on how it can be amended. Article 60 lies within "Section VIII: The Legislative Process, Subsection 2: Amendments to the Constitution". The following is detailed therein:

State constitutions

State constitutions in the U.S. are amended on a regular basis.[9] In 19 states, the state constitutions have been amended at least 100 times.[9]

Amendments are often necessary because of the length of state constitutions, which are, on average, three times longer than the federal constitution, and because state constitutions typically contain extensive detail.[9] In addition, state constitutions are often easier to amend than the federal constitution.[9]

Individual states differ in the difficulty of constitutional amendments.[10] Some states allow for initiating the amendment process through the action of the state legislature or by popular initiative.[10]

California

There are three methods for proposing an amendment to the California State Constitution: by the legislature, by constitutional convention, or by voter initiative. A proposed amendment must be approved by a majority of voters.

With the legislative method, a proposed amendment must be approved by an absolute supermajority of two-thirds of the membership of each house.

With the convention method, the legislature may, by a two-thirds absolute supermajority, submit to the voters at a general election the question whether to call a convention to revise the Constitution. If the majority of the voters vote yes on that question, within six months the Legislature shall provide for the convention. Delegates to a constitutional convention shall be voters elected from districts as nearly equal in population as may be practicable. The constitution does not provide any rules for the operation of the constitutional convention.

With the initiative method, an amendment is proposed by a petition signed by voters equal in number to 8% of the votes for all candidates for governor at the last gubernatorial election. The proposed amendment is then submitted to the voters at a general or special election.

New York

There are two methods of proposing amendments to the New York Constitution. All proposed amendments must be approved by a majority of voters in a referendum.

With the legislative method, an amendment proposal must be published for three months, then approved by an absolute majority of the members of each of the two houses, and approved again in a succeeding term of the houses, with an election intervening. Finally, the amendment proposal must be submitted to the people, and for ratification must be approved by a simple majority.

With the convention method, a constitutional convention must be convened by a majority vote of voters in a general election (referendum) on the question.

Tennessee

There are two methods for proposing amendments to the Tennessee State Constitution: through the legislature and by constitutional convention. Proposed amendments must be approved by a majority of voters in a referendum.

With the legislative method, the Tennessee General Assembly passes a resolution calling for an amendment and stating its wording. This must pass in three separate readings on three separate days, with an absolute majority on all readings. It does not require the governor's approval. It must then be published at least six months before the next legislative election in newspapers of wide and general circulation. (This is done by precedent but is not required by law.) After the election, the proposed amendment must go through the same procedure (absolute majority on three separate readings). Then it is put on the ballot as a referendum in the next gubernatorial election. To be ratified it must again achieve an absolute majority of those voting in the gubernatorial election.

With the convention method, the legislature can put on any ballot the question of whether to call a constitutional convention. It must be stated whether the convention is limited or unlimited—that is, whether it can only amend the current constitution or totally abolish it and write a new one. If limited, the call must state which provisions of the current constitution are to be subject to amendment, and the subsequent convention, if approved, is limited to considering only amendments to the provisions specified in the call. The proposed amendments must then be submitted to the electorate and approved by a majority of those voting in the election. A constitutional convention cannot be held more frequently than once every six years.

Texas

The only method for proposing an amendment to the Texas State Constitution is through the legislature, either in regular or special session. The governor may call a special session, and specify the agenda for the session. To become part of the constitution, proposed amendments must be approved by a majority of voters in a referendum. Texas has had six different constitutions and the current constitution, adopted in 1876, has been amended 474 times.[citation needed]

A proposed amendment must be approved by an absolute supermajority of two-thirds of the elected membership of each house of the legislature. It is submitted to the voters in an election specified by the legislature. The wording of an explanatory statement that will appear on the ballot must be approved by the Texas Attorney General and printed in newspapers. The full text of the amendment must be posted by all county clerks for 30 days before the election.

Washington

The only method for proposing an amendment to the Washington State Constitution is through the legislature and can originate in either branch. The proposal must be approved by a two-thirds majority of the legislature. The proposed amendment is placed on the ballot at the next general election and must be approved by a majority of the voters.