The United States Supreme Court and Foreign Law

With this post, we quickly set aside the issue of interdisciplinarity in comparative law and focus on applied comparative law in a broader sense. Specifically, I would like to look at the question whether the United States Supreme Court (and courts in general) should consider foreign law and practices.

In this regard, Justice Breyer of the United States Supreme Court just published his book The Court and the World: American Law and the New Global Realities. The book essentially is a commented synopsis of recent Supreme Court decisions that mention foreign law. Most of these decisions concerned the interpretation of international treaties or statutes where consideration of foreign law is fairly accepted. Sometimes, however, foreign law was consulted on questions relating to the United States constitution and its interpretation. In particular, issues relating to national security and antitrust triggered a look across borders, but also questions about gay rights and the death penalty.

According to Justice Breyer, foreign law – while by no means binding – could be quite “instructive” in cases involving questions of constitutional interpretation in general and more specifically questions relating to the Eighth Amendment and the death penalty.

“It [the Eighth Amendment] uses the word ‘unusual,’ and the founders didn’t say unusual in what context.”

Generally, judges – and lawyers – across borders could learn from each other. Unfortunately, drawing inspiration from abroad is still very limited – not just for ideological reasons, but also because of lack of understanding foreign law and its terminology.


  • Adam Liptak, Justice Breyer Sees Value in a Global View of Law, The New York Times, September 12, 2015 (available here)

Topics in the Current Issue of the American Journal of Comparative Law

It is the end of the year (how fast time has passed!) and I would like to start a new routine on this blog: periodic literature review. For now, I am planning to do this on a quarterly basis and to start with the American Journal of Comparative Law. Later on, I may decide to review more publications more frequently. If you have any particular request or ideas, feel free to communicate them in the comments section.

Volume 62, issue 3 of the American Journal of Comparative Law (AJCL) was published in December 2014. The first part of the issue represents a write-up of contributions to a symposium with the title “Comparative Constitutional Change: New Perspectives on Formal and Informal Amendment”, held at the annual meeting of the American Association of Law Schools (AALS) in New York early this year. It contains articles by Carlos Bernal, James E. Fleming, Ran Hirschl, Samuel Issacharoff, Stephen Gardbaum, and Richard Albert. Comparative constitutional law is a fascinating discipline at the interface between national constitutional law and international democratization. The focus of the symposium and the ensuing articles are the apparent and not so apparent ways of constitutional change from a comparative perspective.

Besides the symposium part, the current issue of the AJCL contains three major articles in the areas of contract law, freedom of expression/Islamic law, and constitutional/Asian law. The first article, The Political Economy of Regulating Contract by Aditi Bagchi, focuses on the macroeconomic factors that influence contract regulation, in particular whether a legislator decides to act preemptively by issuing mandatory rules of contract or opts for posthoc action through default rules. The second article, Blasphemy, Holocaust Denial and the Control of Profoundly Unacceptable Speech by Neville Cox, examines the recently stirred-up divide between largely unregulated freedom of speech in the West (most notably the United States) and strictly regulated statements on religion in Islamic countries. The third article, Survival of the Fittest(2): The Endurance of the ROC Constitution and the Constitution of Japan by Chien-Chih Lin, compares the different factors that led to the longevity of the constitutions of Japan and the Republic of China.

The current AJCL issue concludes by several book reviews. You can access the website of the current issue of the AJCL here. I hope this quick overview was helpful.

Happy New Year!







My Comments on “A Network-Based Taxonomy of the World’s Legal Systems” by Mathias Siems

Despite the (partially) fierce criticism of a quantitative approach to comparative law, the use of statistics to answer comparative law questions seems to have inspired some new comparative law research. A working paper by Mathias Siems with the title A Network-Based Taxonomy of the World’s Legal Systems uses statistics in order to “develop a difference-based taxonomy in accordance with the idea of legal families.” (p. 10)

After discussing pros and cons of classifications in comparative law, Siems comes up with three groups of four variables ranging from “English as official language” to “Paid annual leave.” He then applies these variables to a dataset of 157 countries in order to determine the difference of each single variable with the same variable for each of the remaining countries. This allows him to plot a histogram for  the distribution of the country differences which in turn allows him to create and graphically represent cluster for all the 157 countries studied. Siems subsequently applies his variables to the legal origins literature concluding – somehow surprisingly – that his “network data does not support the legal origins taxonomy.” (p. 17) The last part of the paper is dedicated to developing an alternative classification of the legal systems of the world. By playing with numbers, Siems comes up with four groups: “The Global Anglosphere”, “The Modern European Legal Culture”, “The Rule by Law or Religion” and the “Weak Law in Transition”.

With his paper, Siems opens an interesting avenue for comparative law research. Statistics in general and network analysis in particular may play a role in helping to answer sometimes longstanding questions in comparative law. Yet, statistics are not inherently objective and they need to be properly applied in order to make use of their full potential. In this regard, Siems’ paper raises several concerns. First, the choice of variables by Siems – while well elaborated though probably extendable from a legal standpoint – is problematic from a statistical viewpoint as he mixes categorical variables (here questions with yes/no answers, e.g. “Islam state religion”) with ordinal (or numerical) ones (where the answer lies on a spectrum, e.g. “literacy rate”). Also, the exact translation of the variables into numbers is not really explained. Second, Siems does not really elaborate on the reasoning behind the thresholds (“cut-offs”) for his clusters. Some representations are based on a 0.11 threshold, others on 0.13. Why these thresholds were chosen remains unclear. Third, the conclusion that the classification of the legal systems according to their legal origins is wrong rests on shaky statistics. Little details are given as to the numbers and the reasoning seems somehow circular. Fourth, Siems selects the number of groups into which legal systems can be divided randomly by playing with different numbers and looking which number of groups makes more sense. This, of course, takes away a lot of objectivity from the study.

Overall, the general idea behind A Network-Based Taxonomy of the World’s Legal Systems by Mathias Siems, i.e. to examine traditional issues of comparative law is very innovative and may potentially shape future comparative law research. As any pioneering work it inevitably faces some challenges – mostly due to the fact that the statistical analysis of networks is complex and at the same time so foreign to the conventional way to think about law.


Mathias Siems, A Network-Based Taxonomy of the World’s Legal Systems, 2014 Working Paper Durham Law School, available here.