When is it permissible to move an issue out of normal politics and treat it as a security issue? How should the security measures be conducted? When and how should the securitization be reversed? Floyd offers answers to these questions by combining security studies' influential securitization theory with philosophy's long-standing just war tradition, creating a major new approach to the ethics of security: 'Just Securitization Theory'. Of interest to anyone concerned with ethics and security, Floyd's innovative approach enables scholars to normatively evaluate past and present securitizations, equips practitioners to make informed judgements on what they ought to do in relevant situations, and empowers the public to hold relevant actors accountable for how they view security.