IACL-AIDC.ORG

The International Association of Constitutional Law || l'Association Internationale de Droit Constitutionnel

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IACL: The International Association of Constitutional Law

The overriding objective of the International Association of Constitutional Law (IACL) is to provide a forum in which constitutionalists from all parts of the world can begin to understand each other’s systems, explain and reflect on their own, and engage in fruitful comparison, for a variety of purposes.

L'AIDC: l'Association Internationale de Droit Constitutionnel

L’objectif premier de l’AIDC est d’offrir un forum dans lequel les constitutionnalistes du monde entier puissent commencer à comprendre le système constitutionnel de chacun, expliquer et réfléchir par eux-mêmes, et se livrer à des comparaisons fructueuses, dans des buts variés.
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The IACL World Congress 2026

Sustainable Constitutionalism: Answers for a Changing World

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The IACL World Congress 2026 || Sustainable Constitutionalism: Answers for a Changing World

The four plenary sessions of the Congress will address the following topics:

  1. Democracy: growth, backsliding, repair and revival
  2. Rule of law: courts as defenders or reformers of constitutionalism
  3. Human rights in reality: access and implementation
  4. Human duties in the human-centred world: constitutionalism and private actors
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Blog

Launched in 2018, the IACL-AIDC Blog aims to provide a user-friendly meeting place for constitutionalists around the world to present their research, share their views, and discuss crucial constitutional law topics, as well as overlooked issues and more technical discussions of constitutional law. The five values of the Blog are to be user-friendly, provide added value, and to be responsive, inclusive and truly global.

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National Associations

The IACL endeavours to ensure that its processes and activities are suited to its diverse membership, whilst at the same time retaining the scientific and scholarly approach on which the credibility of its work depends. The IACL maintains close links with many national and regional associations of constitutional law.

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IACL World Congress, Mexico
Workshop 9: Proportionality as a constitutional principle

The proportionality principle may be applied to reconcile conflicting constitutional provisions, either as a precondition for the application of a constitutional principle or as a free-standing constitutional requirement.

Where proportionality provides a justification of the limitation of a right or a freedom, it may be found in the constitutional text (for example in the Declaration of the Rights of Man and the Citizen of 1789, on the subject of the imposition of a penalty or interference with property rights). However, a constitutional court may apply the proportionality principle even in the absence of any express constitutional provision to that effect.

Proportionality enables the courts to develop a hierarchy of fundamental rights and liberties, or a hierarchy of those rights and liberties and public interests.

Proportionality may also be raised by a court as a principle which the legislature should respect quite independently of any need to reconcile constitutional principles with one another.

The principle is also applied by the European Court of Human Rights for the purposes of the margin of appreciation allowed to states in applying the Convention.

Against this background a number of issues arise:

  • What is the extent of the court’s power in applying the proportionality principle? Is it limited or unlimited?
  • Could the proportionality principle justify a court interfering with the legislative function to the extent of determining substantively where the public interest lies?
  • Could the proportionality principle undermine a judicial system that is supposed to be based on common values by substituting for it a system based on reaching a consensus as to different concurrent values.
  • Does the application of the proportionality principle enhance the discretionary functions of the court, so that giving effect to substantive legislative requirements becomes secondary to consideration of the rationality of challenged decisions.
  • Are there any non-derogable principles, i.e. principles which are not subject to proportionality review?
  • Does the principle of proportionality guarantee to states a degree of freedom of action under the European Convention of Human Rights, or is the principle designed to limit the freedom of action of states in deciding how to give effect to Convention rights?
  • How is the principle of proportionality given effect by constitutional courts? Do its effect depend upon the kind of review (abstract, concrete, ex ante, ex post, by way of appeal from an inferior court or the exercise of original jurisdiction by a constitutional court)?

These questions are not exhaustive. The workshop is open to those interested in these and other approaches to proportionality in constitutional law.

Chairs:
Professors Bertrand Mathieu [This email address is being protected from spambots. You need JavaScript enabled to view it.] and Dawn Oliver [This email address is being protected from spambots. You need JavaScript enabled to view it.]

Please see further:

  • Establish a new IACL Research Group

    Thematic Research Groups are a very special part of the IACL. Although hosted by, and therefore existing under the umbrella of the IACL, these Research Groups operate independently. They conduct research and publish findings, and they organise private meetings, public events and other activities. They contribute richly to the identity and reputation of the IACL and benefit from the IACL’s affiliation and endorsement.