The report presents the design of a scenario-based approach to studying the will to defend. The procedure is based on a data collection process that takes place digitally over time, with an interval of one or two weeks between the measurement occasions. The approach is designed as a result of a problematization of previous research that takes place initially in the report. A large majority of previous studies focus on willingness to defend through cross-sectional studies that show what percentage of the respondents answer yes or no when queried about whether Sweden should defend itself against an attack from a foreign power. Although these investigations are solid and the conclusions valid, their precision is low regarding various factors that could influence the actual willingness to defend in a positive or negative direction. A scenario-based tool can improve our knowledge about the determinants of the will to defend. It cannot, however, replace a societal discussion about what it should be. The approach presented here provides better conditions, both for responsible authorities and researchers, to reliably measure the willingness to defend among different population groups. The report also prompts others, organisations as well as individuals, to reflect on what roles and needs exist in the Swedish society and who would defend the country if the unthinkable were to happen.