Researching Comparative Constitutional Law

By Julienne E. Grant

Julienne E. Grant serves as Reference Librarian/Foreign & International Research Specialist at the Loyola University Chicago School of Law Library. She has published articles in Legal Reference Services Quarterly and the International Journal of Legal Information. She also co-authored a chapter (with Teresa M. Miguel-Stearns) in Latin American Collection Concepts: Essays on Libraries, Collaborations and New Approaches (McFarland, 2019). In addition, Ms. Grant is a regular contributor to the DipLawMatic Dialogues blog, which is associated with the Foreign, Comparative, and International Law Special Interest Section (FCIL-SIS) of the American Association of Law Libraries (AALL). She is a member of the FCIL-SIS and served as chair of its Latin American Law Interest Group from 2013 to 2017. Ms. Grant earned a B.A. magna cum laude in Spanish from Middlebury College; an M.A. in Ibero-American Studies from the University of Wisconsin-Madison; an M.A.L.S. from Rosary College (now Dominican University); and a J.D. cum laude from DePaul University. She also has a Certificate in Editing from the University of Chicago Graham School.

Published July/August 2020

1. What is a Constitution?

Professor Aalt Willem Heringa of Maastricht University posits that the word “constitution” has both narrow and broad meanings in a socio-political context. Its narrow definition, according to him, is “a central written document that sets out the basic rules that apply to the government of socio-political entities, in particular states.”[1] In a broader sense, however, he asserts that “a constitution comprises the entire body of fundamental rules that govern that socio-political entity: be they contained in a central document or in many documents, be they written down or be they customary rules. Substantively, therefore, a constitution is a body of law that: attributes power to public authorities; regulates the fundamental relations between public authorities; and regulates the fundamental relations between the public authorities and the individual.”[2] Thus, with the broader definition, a country or other polity may have a constitution without the existence of a central written document (such as in the case of the United Kingdom).

This guide will address the research techniques and resources for comparative constitutional law in the broadest sense of Professor Heringa’s definition of a constitution.

2. What is Comparative Constitutional Law?

Contemporary scholars have struggled to define comparative constitutional law and its related terms, such as comparative constitutionalism. In his book Comparative Matters: The Renaissance of Comparative Constitutional Law (Oxford UP, 2014), Professor Ran Herschel of the University of Toronto writes, “Since its birth, comparative constitutionalism has struggled with questions of identity. There is considerable confusion about its aims and purposes, and even about its subject—is it about constitutional systems, constitutional jurisprudence, constitutional courts, or constitutional government and politics? It also remains unclear whether comparative constitutional law is or ought to be treated as a subfield of comparative law, a subfield of constitutional law, or an altogether independent area of inquiry.”[3]

For purposes of this guide, comparative constitutional law will be considered a field within the larger and more general discipline of comparative law, a topic that is expertly addressed in Hester Swift’s 2016 update to GlobaLex’s “Comparative Law.” Ms. Swift credits comparative law’s recent resurgence in importance to two factors: 1) the increased globalization of world trade; and 2) a general trend towards the harmonization of laws, and more specifically, towards codification within the European Union (EU).

The modern vitalization of constitutional law in a comparative context has occurred concurrently—in legal and judicial practice, as well as in academia. Professor Monica Claes (also of Maastricht University) attributes this dramatic growth in interest to a number of factors: an increase in constitutional activity across the world; the growing importance of constitutions and constitutional law in public life (including constitutional adjudication); an expanding interest in national identity; and the constitutionalization trend in European and international governance.[4]

Professor Heringa further describes the benefits of the practice of comparing constitutions: 1) the process aids in appreciating and understanding a researcher’s own constitutional system; 2) it provides useful material for constitution building and constitutional engineering; and 3) it establishes a basis for the creation and development of international organizations and their institutions (such as the EU and the Court of Justice of the European Union).[5]

3. Research Overview

That the contours of comparative constitutional law are not sufficiently clear has implications for researchers. Specifically, its scope intersects with that of other fields and disciplines, such as political science, history, human rights, philosophy, and anthropology; accordingly, researchers should not limit their investigations to traditional legal research sources like law journals and legal treatises. Professor Hirschl argues that “any attempt to portray the constitutional domain as predominately legal, rather than imbued in the social or political arena, is destined to yield thin, ahistorical, and overly doctrinal or formalistic accounts of the origins, nature, and consequences of constitutional law.”[6]

Similarly, researchers should recognize the semantic variations in the name of the field itself. For instance, comparative constitutional law is often equated or associated with comparative constitutional studies, comparative constitutionalism (as noted above), comparative constitutional change, comparative constitutional review, and comparative judicial politics. Researchers also need to be aware that general works on comparative law may include scholarship on the more specialized field of comparative constitutional law.

This guide proceeds with the assumption that there are multiple areas of research activity within the field. There are, for example, secondary works about comparative constitutional law, its research agendas, and its investigative methodologies. Other secondary sources present country-by-country descriptions of national constitutional histories and contents. Statistical studies have been designed that compare constitutional texts, themes, and structures—the results of which have been published in scholarly books and journal articles. Another investigative area focuses on judicial, or more specifically, constitutional review; that is, the process utilized to test and decide the constitutionality of legal acts. The scope of this area includes examining the decisions of constitutional courts and their judicial equivalents.

As such, the goal of this guide is to provide a roadmap for the numerous types of research conducted within the realm of comparative constitutional law. The guide first presents introductory materials about the field itself, as well as electronic platforms that can assist with all facets of researching comparative constitutionalism. The general category of secondary sources is addressed next, which identifies the field’s most important encyclopedic works; presents techniques for locating helpful books; lists relevant monographic series; identifies the field’s principal journals; and recommends sources for finding pertinent articles, theses, and dissertations. The guide then turns to a list of helpful websites, and then the constitutional scholar’s primary tools for conducting comparative work—constitutional texts and court decisions. News sources and blogs are next, followed by sources for historical constitutional research. The guide concludes with a compiled list of international and regional organizations that focus on constitutional law.

Within the guide’s content, emphasis is placed on English-language resources, although many of the techniques described below will lead to information in other languages, including constitutions in the vernacular. Greater focus is also placed on national constitutions, rather than those at the subnational level, such as U.S. state constitutions. An *asterisk* in the text indicates a subscription database.

4. Introductory Materials

The following publications provide in-depth introductions to the field of comparative constitutional law, including its research goals and investigative methodologies.

5. Electronic Research Guides

The online guides listed below serve as general pathfinders for comparative constitutional law research and are good starting points.

6. Secondary Sources

The study, analysis, and comparison of constitutions has yielded a large body of secondary literature that includes encyclopedias, books, monographic series, journal articles, and graduate theses and dissertations. These types of resources are addressed below.

6.1. Encyclopedias

The following list includes English-language encyclopedias in print and electronic format that are useful for all areas of comparative constitutional law research.

6.2. Books & Monographic Series

Library of Congress Subject Headings (LCSHs) are assigned to books held in U.S. libraries and beyond and are helpful for identifying subject-specific monographs and other materials. There is no single LCSH for the field of comparative constitutional law; items on this subject are generally tagged with two LCSHs—"Constitutional Law” and “Comparative Law.” Subtopics of comparative constitutional law, such as constitutional amendments, civil rights, and habeas corpus are assigned single headings and those may be combined with a jurisdiction: e.g., “Constitutional Amendments—Brazil.” The Library of Congress provides an online searchable database of LCSHs that is relatively easy to use.

Noteworthy are several monographic series that focus on comparative constitutional law, such as Elgar Monographs in Constitutional and Administrative Law, edited by Professors Rosalind Dixon, Susan Rose-Ackerman, and Mark Tushnet. Elgar also publishes the Research Handbooks in Comparative Constitutional Law series, edited by Professor Tom Ginsburg of the University of Chicago Law School. Professor Ginsburg also serves as editor of the Cambridge series Comparative Constitutional Law and Policy, along with Professors Zachary Elkins and Ran Hirschl. Routledge publishes the series Comparative Constitutional Change, edited by Professors Richard Albert, Xenophon Contiades, Thomas Fleiner, and Alkmene Fotiadou.

For monographs on the constitutional law of individual countries, the LCSH “Constitutional Law” may be combined with individual countries: e.g., “Constitutional Law—Spain.” Wolters Kluwer publishes a series on comparative law that includes separate books on the constitutional law of various countries, such as Cameroon, China, and Hong Kong. The content of these books is derived from the aforementioned International Encyclopaedia of Laws. Hart Publishing offers the series Constitutional Systems of the World with separate monographs on Brazil, Myanmar, and Poland, among others. The general editors of the series are Professors Peter Leyland, Andrew Harding, Benjamin L. Berger, Rosalind Dixon, and Heinz Klug. In 2013, Bloomsbury published a European and National Constitutional Law Series, comprising six books edited by Professor Monica Claes.

6.3. Journals & Periodical Indexes

Listed below are English-language serials that focus on constitutional law from a global or regional perspective. Note that academic journals that center on the constitutional law of a single jurisdiction may also be useful for comparative constitutional law research. Likewise, periodicals that concentrate on comparative law generally may include articles on constitutional law topics. Each title below is followed by a parenthetical with the publisher’s name, as well as an indication if the publication is open access.

The following online periodical databases and indexes will also help identify and locate relevant articles. Searches in Google Scholar and SSRN may also be useful in this respect.

6.4. Theses & Dissertations

Often overlooked by researchers, theses and dissertations contain exhaustive research and extensive bibliographies and may serve as useful sources of information on comparative constitutional law subjects. Along with the web platforms listed below, many universities post digital copies of their own students’ theses and dissertations.

7. Useful Websites

Listed below are several websites that contain potentially valuable information for scholars engaged in comparative constitutional law research.

8. National Constitutions & Associated Legislation

For online guides to researching national constitutions, try Googling the term “LibGuide” with the name of the jurisdiction and “constitution” or “constitutional law.” The Bodleian Libraries at the University of Oxford have compiled legal research guides for various countries that include separate sections on their constitutions. Some examples of these helpful guides are listed below, along with other useful research platforms for selected domestic constitutions. GlobaLex articles on specific countries may also help identify sources of information about those nations’ constitutions. For Latin America, see Dante Figueroa and Jonathan Arendt’s GlobaLex contribution on “Current Constitutional Developments in Latin America,” most recently updated in 2016.

Also noteworthy is the interactive tutorial “How to Research Foreign Constitutions”* (Brian Huddleston, Loyola University College of Law, New Orleans), which is posted on the Web platform of the Center for Computer-Assisted Legal Instruction (CALI). This excellent lesson explains how to utilize various electronic resources, including Westlaw* and Lexis,* to research the constitutions of jurisdictions outside of the United States. A subscription to CALI is required for access.

An important research activity within the field of comparative constitutional law is the analysis of a selected spectrum of constitutional texts, themes, or designs. Several electronic resources provide access to the full texts of the world’s constitutions and associated laws, many in English-language translation. Below are listed the most useful of these resources. Note that national parliament and government websites often provide direct access to the most current version of a country’s constitution, with amendments directly incorporated into the constitutional text. The annual Guide to International Legal Research,* compiled by staff of the George Washington International Law Review, is available in print and online in LexisNexis. Use the volume’s “Subject Matter Index,” and then under the heading of “Constitutions,” to identify sections in the guide that cover the constitutions of individual nations.

9. Constitutional Review

A constitution, be it written or unwritten, is generally recognized as the supreme law in a jurisdiction’s legal system. According to Professor Günter Frankenberg (Goethe University), “Superiority is ascertained, technically, by the systematic ranking of constitutional norms at the top of the legal hierarchy, above the ordinary laws, and by the methodological rule that laws have to be interpreted in conformity with the constitution.”[7] Constitutional review (sometimes used synonymously with “judicial review”) is the process by which a judicial authority checks legal acts for compliance with the constitution. A judicial authority can take different forms, but for the most part, it follows a U.S. model (a supreme court) or a European model (a constitutional court).[8]

In the U.S. model, constitutional review is included within the overall subject-matter jurisdiction of a country’s highest appellate court. In contrast, in the European model, a specialized constitutional court is charged with the task of determining the constitutionality of legal acts. This is, of course, a simplified description, as there are hybrid forms, and in some instances, the judicial authority for constitutional review is not a court per se. Researchers are referred to the Max Planck Encyclopedia of Comparative Constitutional Law* for detailed descriptions and examples of the various kinds of constitutional review. For a chart of constitutional review models with the corresponding countries that utilize them, see Nova Univerza (New University), Professor Arne Marjan Mavčič’s useful Concourts.net website.[9]

Below are recently published secondary sources on constitutional review in a comparative context, along with tips for identifying and locating the decisions of constitutional courts and their judicial equivalents.

9.1. Secondary Sources

The LCSH “Constitutional Courts” will identify books on the subject in online library catalogs. The “Constitutional Courts” heading can be combined with a region or single jurisdiction, such as “Constitutional Courts–Italy.” Another relevant LCSH is “Judicial Review,” which can likewise be combined with a specific region or country. The IFLP mentioned above includes the indexing terms “Judicial Review” and “Constitutional Courts,” which will pinpoint journal articles. The following is a sample list of recent secondary sources (2017–) related to the topic of comparative constitutional review.

9.2. National Court Decisions

A good resource for determining where national court decisions, including those of constitutional courts, are published is the twentieth edition of The Bluebook (Table 2, Foreign Jurisdictions). The Mavčič book listed above indicates whether a national body of constitutional review publishes its decisions in an official gazette or digest, legal journals, electronically, and/or in “other forms.” Most national courts and other judicial bodies post their decisions on their websites, although English-language translations of opinions tend to be scarce. The following resources also publish national court decisions periodically.

The electronic Bulletin on Constitutional Case-Law, compiled by the Council of Europe’s European Commission for Democracy through Law (the “Venice Commission”) reports on decisions of constitutional courts and their jurisdictional equivalents in Europe and beyond. The bulletin is released three times per year; free email subscriptions are available. The cases in the bulletin are added to the Venice Commission’s CODICES database. This useful platform contains the full texts and English-language summaries of thousands of decisions, including those from the Court of Justice of the European Union (CJEU) and the European Court of Human Rights (ECHR), which involve constitutional questions. The Venice Commission site also includes a list of constitutional review institutions with their website addresses.

9.3. International & Regional Tribunal Decisions

Some international and regional tribunals hear appeals from national courts, including constitutional courts, and have certain functions of constitutional review. According to Professor Mavčič, these tribunals include the CJEU, the ECHR, the European Free Trade Association Court, the Inter-American Court of Human Rights, the Central American Court of Justice, and the African Court on Human and Peoples’ Rights.[10] All of these tribunals’ decisions are posted on their respective websites; the ECHR’s caselaw database, HUDOC, allows narrowing by ECHR opinions that reference a constitutional court in the text (see the “Court” heading under “More Filters”).

Professors Federico Fabbrini (Dublin City University) and Miguel Poiares Maduro (European University Institute) have coined the term “supranational constitutional courts” to describe those international tribunals that have a constitutional character and meet six requirements: jurisdiction extending beyond inter-states disputes; possession of a set of substantive powers of review analogous or equivalent to those of national constitutional courts; “subjectivization” of underlying treaties; development of a hermeneutic that is autonomous from international law; embracement of the core doctrines of constitutional law; and widespread social and institutional support.”[11] Professors Fabbrini and Maduro posit that the CJEU is the paradigmatic example of a supranational constitutional court and that the ECHR is moving in that direction.

The actual relationship between European national courts and the CJEU is highly complex and unsettled. Leiden University Professor Darinka Piqani has noted the circumstances when domestic tribunals and the CJEU tend to cooperate: preliminary rulings on EU law, uncertainty about the constitutionality of national implementing measures, questions on the constitutionality of EU treaties, and controversies about the constitutional compatibility between national legislation and EU law.[12] It is worth pointing out that the EU attempted to create and implement a Constitution for Europe in the early 2000s, but the initiative failed when French and Dutch voters voted against its ratification in 2005.

10. Current Awareness: News Sources and Blogs

Newspaper and news websites, as well as blogs, can be excellent sources for information on constitutional developments around the world. Onlinenewspapers.com provides a comprehensive directory of the world’s newspapers with links to their websites.

The following is a list of selected news sources and blogs that cover constitutional law in a regional or global context. Note that a comprehensive collection of links for legal-related blogs is available on JUSTIA’s BlawgSearch; the lists there are organized by practice area, geographic focus, and by law school sponsorship.

11. Digital Archives & Historical Materials

The following resources are useful for conducting historical comparative constitutional law research, as well as identifying more contemporary sources.

12. Institutes, Centers & Associations

Listed below are various initiatives and organizations that focus on comparative constitutional law or include that topic within their realm of activities. Note that many jurisdictions have their own associations or societies devoted to the study of national constitutional matters; e.g., the Australian Association of Constitutional Law.


[1] Aalt Willem Heringa, Constitutions Compared: An Introduction to Comparative Constitutional Law, 5th ed. (Cambridge, UK: Intersentia, 2019), 4.

[2] Id.

[3] Ran Hirschl, Comparative Matters: The Renaissance of Comparative Constitutional Law (Oxford, UK: Oxford University Press, 2014), 4.

[4] Monica Claes, “Constitutional Law,” in Elgar Encyclopedia of Comparative Law, 2nd ed., ed. Jan M. Smits (Cheltenham, UK: Edward Elgar, 2012), 224–25.

[5] Heringa, supra note 1, at 1.

[6] Hirschl, supra note 3, at 152.

[7] Günter Frankenberg, “Comparative Constitutional Law,” in The Cambridge Companion to Comparative Law, eds. Mauro Bussani and Ugo Mattei (Cambridge, UK: Cambridge University Press, 2012), 171.

[8] For detailed explanations of judicial review and the various constitutional review court models, see Rainer Grote, “Judicial Review,” and Virgilio Afonso da Silva, “Constitutional Courts/Supreme Courts, General,” in Max Planck Encyclopedia of Comparative Constitutional Law (Oxford, UK: Oxford University Press, 2018).

[9] See Arne Marjan Mavčič, Models of Constitutional/Judicial Review, The Legal Information System (last visited Jul. 14, 2020). The chart is near the bottom of the page before the footnotes.

[10] Id.

[11] Federico Fabbrini and Miguel Poiares Maduro, “Supranational Constitutional Courts,” in Max Planck Encyclopedia of Comparative Constitutional Law (Oxford UP, 2018).

[12] Darinka Piqani, “Relation of Supreme Courts/National Courts to EU Courts,” in Max Planck Encyclopedia of Comparative Constitutional Law (Oxford UP, 2018).