Jonathan was Research Director at the European Leadership Network.
He previously served as senior policy officer within the Security Policy Department, Division of Non-Proliferation, Disarmament and Nuclear Affairs, at the Ministry of Foreign Affairs of the Netherlands, where he worked on files related to nuclear non-proliferation, disarmament and nuclear security. Prior to joining the Dutch MFA, he was a research fellow at the Centre for Conflict and Security Law (attached to Utrecht University and the University of Amsterdam in the Netherlands) specialising in arms control law and nuclear security, where among other things he served as advisor to the Dutch government and as nuclear security expert for the 2014 and 2016 Nuclear Security Summits.
Jonathan has conducted extensive research on various aspects of the international law of arms control pertaining to weapons of mass destruction, has written and published widely on topics related to nuclear arms control, and assistant edited the primary legal commentary on the Chemical Weapons Convention published by Oxford University Press.
He holds a PhD in public international law from the University of Amsterdam (dissertation: “Preventing Nuclear Terrorism: International Law and Nuclear Security Governance”).