President Barack Obama has announced his intention to host, in April 2010, an International Nuclear Security Summit. After almost a decade characterized by ad hoc initiatives aimed at curbing the illegal trafficking of nuclear related material, the new US administration seems to be eager to work in order to coordinate the different bilateral and multilateral programs and achieve some sort of institutionalization of the different initiatives. The Nuclear Security Summit might be the first building block of a new international nuclear proliferation regime but in order to reach a successful conclusion the US government will have to weigh the advantages of institutionalization against the need for flexibility and wider participation.