Few tasks could be more important than keeping nuclear weapons and their essential ingredients out of terrorist hands. The world community has made substantial progress in improving security for such stocks since the early 1990s, including through the nuclear security summits in 2010-2016.
Bunn, Matthew, Nickolas Roth, and William H. Tobey. "Revitalizing Nuclear Security in an Era of Uncertainty." Project on Managing the Atom, January 2019.