For nations facing expansionist and revisionist neighbours such as Russia or China, a total defence approach provides a mechanism to protect both territorial integrity and political sovereignty. A key component for any effective total defence concept is volunteer, citizen- soldier territorial defence forces (TDF). This paper emphasises the role these territorial formations play as the critical snap link between the military and civilian population in such a national defence strategy. The territorial defence forces, like the snap link in mountaineering, connect the military to the civilian population in a way to ensure popular support for national resistance efforts. The article offers the historical example of Switzerland as an exemplar of total defence from 1939 to 1991 and demonstrates the role its citizen-soldier forces played in linking the population to overall resistance efforts. This Swiss historical experience provides three main concepts for consideration today: (1) the creation of a government directed and functional levée en masse that mobilizes the entire population to support total defence; (2) the establishment of a national redoubt or refuge, either in-country or abroad, to provide sanctuary for the resistance movement; (3) and the organisation of specialised, multi-crisis capable territorial units for the full range of total defence missions.