Introduction: transnational law oversteps traditional categories

In their book Transnational Legal Problems, first published in 1968, Detlev Vagts and Henry Steiner espoused Philip Jessup's term ‘transnational law’ as ‘more than congenial’ to them. ‘Transnational law’ was meant by Jessup ‘to include all law which regulates actions or events that transcend national frontiers. Both public and private international law are included, as are other rules which do not wholly fit into such standard categories’. In their seminal book, Steiner and Vagts sought to give principal attention to problems that were ‘relevant not only to governments but also to the private participants – individual or corporate – in transnational life’. They defied ‘rigid compartments’, and instead dealt with all kinds of legal issues, including foreign investment and multinational enterprises (MNEs), ‘on a spectrum between the extremes of “national” and “international” law, or on one between “private” and “public” law’.

With that approach, Detlev Vagts contributed to overcoming the public–private split in international law. That catchword denotes the distinction between a public and a private realm of life, and goes hand in hand with the distinction between State and society, or between State and market. The blurring of these spheres seems particularly obvious with regard to economic law, and has been reinforced by the phenomenon which became generally known as globalisation in the 1990s. But although the erosion of the public–private split can usefully be captured with the notion ‘transnational’, conceptual ambiguities and potential misunderstandings with regard to the key terms remain.