Having introduced a comparison of French and U.S. approaches to legal pluralism in a transnational legal world develops, we now consider answers to our threshold question: How does the transnational legal world develop?
Transnational law develops through:
► cross-referencing,
► efforts to harmonize, and
► creation of hybrid rules of substance and procedure.
In both the European and the U.S. legal systems, the last method is rarely used. It is true that some hybrid rules have been created. An example is the hybridisation of the accusatorial and inquisitorial criminal procedure rules that occurred first in the ad hoc tribunals and later at the International Criminal Court. But these rules – which increase judicial powers in the preliminary phase, transmit dossiers to the trial judge, and accord more prominent roles to victims – do not directly affect national legal orders.
In the United States, much has been debated about the 1st option,
called cross-referencing or, sometimes, consultation; that is, the citation by U.S. judges of decisions handed down by judges of foreign constitutional and international courts. Most salient are 2 U.S. 
Supreme Court judgments, Lawrence v. Texas (2003) and Roper v. Simmons (2005). The latter issued during a Term when the Court considered or referred to foreign law in at least 6 cases, according to Justice Stephen G. Breyer (above). In his foreword to my book Ordering Pluralism (trans. Naomi Norberg 2009), Breyer wrote that "six out of a total docket of 79 indicates the increasingly routine nature" of this method in American cases.
In France, meanwhile, the main concern is the middle option, harmonisation. Jurists focus on the changes that European efforts to harmonise different national systems imposes on criminal, contract, and other sectors of French law.
Harmonisation is a very complex process, entailing both more and less integration than either of the other 2 options:
Transnational law develops through:
► cross-referencing,
► efforts to harmonize, and
► creation of hybrid rules of substance and procedure.
In both the European and the U.S. legal systems, the last method is rarely used. It is true that some hybrid rules have been created. An example is the hybridisation of the accusatorial and inquisitorial criminal procedure rules that occurred first in the ad hoc tribunals and later at the International Criminal Court. But these rules – which increase judicial powers in the preliminary phase, transmit dossiers to the trial judge, and accord more prominent roles to victims – do not directly affect national legal orders.
In the United States, much has been debated about the 1st option,
called cross-referencing or, sometimes, consultation; that is, the citation by U.S. judges of decisions handed down by judges of foreign constitutional and international courts. Most salient are 2 U.S. 
Supreme Court judgments, Lawrence v. Texas (2003) and Roper v. Simmons (2005). The latter issued during a Term when the Court considered or referred to foreign law in at least 6 cases, according to Justice Stephen G. Breyer (above). In his foreword to my book Ordering Pluralism (trans. Naomi Norberg 2009), Breyer wrote that "six out of a total docket of 79 indicates the increasingly routine nature" of this method in American cases.In France, meanwhile, the main concern is the middle option, harmonisation. Jurists focus on the changes that European efforts to harmonise different national systems imposes on criminal, contract, and other sectors of French law.
Harmonisation is a very complex process, entailing both more and less integration than either of the other 2 options:
Harmonisation and cross-referencing
Compared with cross-referencing, harmonisation requires more integration. Cross-referencing assumes the priority of domestic law; in contrast, harmonisation involves a hierarchy in which an abundance of international law is binding on the national legislative authority. That international law derives, moreover, from both poles of the bipolar European legal system discussed in my last post:
► Respecting the European Union pole, France’s Conseil d’État (right) observed in 2000 that since the 1960s the Community had produced more than 68,000 acts supposed to be integrated to French law.
► Respecting the Council of Europe pole, the indirect effects of decisions by the European Court of Human Rights (below left) against France must be noted. In 1990 that Court condemned France twice -- in Huvig and Kruslin, which challenged wiretapping without any legal basis -- and France adopted a new law within a year. In Medvedyev (2008), a Court panel ruled that in France the prosecutor is not independent enough to satisfy the due process principle enshrined in Article 5 of the Convention on Human Rights and Fundamental Freedoms. Should the Court’s Grand Chamber confirm this finding of violation, the French government likely will have to delay and revise a pending plan to transfer more power from the investigating judge to the prosecutor, about which I wrote an op-ed last summer. (Prior IntLawGrrls post)
Compared with cross-referencing, harmonisation requires more integration. Cross-referencing assumes the priority of domestic law; in contrast, harmonisation involves a hierarchy in which an abundance of international law is binding on the national legislative authority. That international law derives, moreover, from both poles of the bipolar European legal system discussed in my last post:
► Respecting the European Union pole, France’s Conseil d’État (right) observed in 2000 that since the 1960s the Community had produced more than 68,000 acts supposed to be integrated to French law.► Respecting the Council of Europe pole, the indirect effects of decisions by the European Court of Human Rights (below left) against France must be noted. In 1990 that Court condemned France twice -- in Huvig and Kruslin, which challenged wiretapping without any legal basis -- and France adopted a new law within a year. In Medvedyev (2008), a Court panel ruled that in France the prosecutor is not independent enough to satisfy the due process principle enshrined in Article 5 of the Convention on Human Rights and Fundamental Freedoms. Should the Court’s Grand Chamber confirm this finding of violation, the French government likely will have to delay and revise a pending plan to transfer more power from the investigating judge to the prosecutor, about which I wrote an op-ed last summer. (Prior IntLawGrrls post)
Harmonisation and hybridisation
Compared with the 3d option of hybridisation, however, harmonisation involves less integration This is because each member state enjoys a margin of appreciation that precludes application of strictly identical rules throughout Europe. As articulated in Handyside v. United Kingdom (1976) and later judgments, the margin-of-appreciation concept operates to limit the jurisdiction of the European Court of Human Rights, particularly in areas in which differences among members states are so strong and so deeply linked to national cultures that it seems impossible for international judges to impose the same rule on every state. Examples include areas such as abortion, euthanasia, and privacy.
The national margin of appreciation excludes binary reasoning: it imposes not an obligation of strict conformity, which bars all variation, but rather an obligation of compatibility, which permits some differences in application of European legal norms.In short, the margin of appreciation involves gradation-based reasoning -- fuzzy logic, as I have called it -- and accepts incomplete integration.
Not all differences are accepted, however. The concept preserves some gradation of integration, for it assumes limits which must not be exceeded. Examples:
► Abortion may be subject to limitations by the state that are strict, as in Ireland or Poland, or not so strict, as in Germany. But, as the Court established in Tysiac v. Poland (2007), the domestic law must effectively implement the Europe-wide right to abortion.
► Wiretapping may be controlled very differently in each European national system -- by administrative authority, for instance, or by a judge or a parliamentary commission. The Court has not relinquished its right to review such mechanisms, but has limited review to those deemed incompatible with Europe-wide norms.
This graduated approach has some resonance among U.S. jurists. Justice Breyer proposed in Heller (2008), which entailed "review of gun control regulation," U.S. courts ought to embrace an "interest balancing inquiry." Breyer considered deference to legislative appreciation to be "particularly appropriate" given that the decision was made "by a local legislature, with particular knowledge of local problems and insight into appropriate local solutions." The consequence is that different localities may seek to solve similar problems in different ways. Breyer’s dissenting opinion in Heller:
The Framers recognized that the most effective democracy occurs at local levels of government, where people with firsthand knowledge of local problems have more ready access to public officials responsible for dealing with them.
(internal quotation marks omitted) This statement is not so different from those in which the European human rights court has considered that national courts are better situated than European judges to determine the proper scope of restrictions based on public order.
