Paradiplomacy is international relations conducted by subnational or regional governments on their own, with a view to promoting their own interests. With globalisation, non-state regions play an increasingly influential international role. Regions, federal states, provinces and cities seek their way to promote trade, investments, cooperation and partnership in a long list of subjects and account for a significant part of today's cross-borders contacts. This trend raises new interesting questions concerning Public International Law and opens a debate on the future of the state system that has provided the grounds for the international political order in the last centuries.
Although the term "paradiplomacy" would be casually employed in the 1980s, it was introduced into the academic debate by the Canadian scholar Panayotis Soldatos. The American author Ivo Duchacek further developed the concept and became one of its main theoreticians. Other current denominations for paradiplomacy and related concepts are: "multilayered diplomacy", "substate diplomacy" and "intermestic affairs". This latter concept expresses a growing trend to the internationalization of domestic issues, which takes local and regional concerns to the centre stage of international affairs.
The intention of local governments is thus to promote development by exploring complementarity with partners facing similar problems, with a view to joining forces to arrive at solutions more easily. In addition, they explore opportunities alongside international organizations that offer assistance programs for local development projects.
In its "decentralized" dimension, international cooperation is a phenomenon that emerged following the Second World War, when local governments in Europe - especially those in France, which were active coordinators of this new form of interaction - signed twinning agreements, principally with German local governments, in order to promote peaceful coexistence and the reconstruction of Europe. At that time, the twinning agreements had a strong cultural and political character while decentralized cooperation had the overarching aim of maintaining peace in the postwar period. However, from the 1970s, the interdependence created by globalization in different fields combined with the evolution of the concept of cooperation (from an assistance-driven to a developmental approach) to elevate the nature of the agreements to another level. At that point, local governments, as they acquired greater autonomy, recognized the importance of international issues in their day-to-day processes and saw decentralized cooperation as a means of overcoming their regional limitations, whether economic, technological, social, or others. From then on, the international participation of local governments has been increasingly evident in practice.