Russia’s invasion of Ukraine has moved attention within International Security back to Great Power Politics and interstate war, and away from phenomena like ‘foreign terrorist fighters’ and lone actor terrorism. Is the War on Terror paradigm receding? This paper argues that counter-radicalisation imaginaries and counter-extremism programming will all remain stubbornly present despite the shift back to interstate war. The resilience of domestic War on Terror policies will stem from their integration within local municipality activity and social policy during the second decade of the 21st century. These policy areas and levels are detached from the international security community, meaning that shifts in attention at the global level will have little effect upon localised national security practices. The paper then interrogates how counterterrorism agendas have so successfully entered the world of social policy and local public administration, using genealogical methods to trace how social security and crime prevention were historically prefaced upon defence. The paper traces the policy paradigm of ‘social defence’ which dominated mid-20th century international organisations, targeting non-criminal juveniles with pre-emptive interventions to prevent ‘dangerous persons’ imperilling society. Effectively, this untold history of crime prevention in Europe demonstrates the profound interlocking of national security, social policy and defence across the 20th century, with implications for the resilience of this triad.