There have been times when public and private international law were closely related. As a means to solve conflicts of sovereign jurisdiction, conflicts law used to be considered as an integral part of the law of nations. Even after Savigny shifted the focus of private international law from the spatial reach of national law to the geographical ‘seat’ of a legal relationship, it was still thought that its rules were, or should be, endorsed by the international legal community. At the beginning of the 20th century, however, public and private international law started to drift apart. It is now generally accepted that states have no mutual obligation with regard to the solution of conflicts cases: private international law is basically national law.

Nevertheless, most states are still prepared to adapt their conflicts-of-law rules to universal standards. National differences were mitigated by the acceptance of party autonomy, proper law exceptions, and a reduction of the nationality principle. The methodological gap caused by the American ‘conflicts revolution’ is gradually being bridged by a more flexible, policy-oriented approach in Europe, and by a return to ‘rules’ in the United States. These developments tend to promote the adoption of universal rules and principles. As academic disciplines public and private international law may have gone their separate ways, but they are still united by their common history, their objectives, and, increasingly, by the universal acceptance of their standards.