This chapter identifies relevant security threats related to the spread of propaganda and disinformation under the new circumstances of the online environment and reacts to the findings and conclusions of the previous chapters. First, the securitisation of propaganda and disinformation is outlined, including the process of change from traditional military security and regime security to societal security. This goes hand in hand with the categorisation of current propaganda and disinformation actors with state and non-state backgrounds—authoritative regimes, illiberal political forces, or terrorists. The chapter then focuses on the strategies and tactics of contemporary creators of propaganda and disinformation and their impacts on targeted audiences, such as the disruption of democratic discourse and trust in institutions, election manipulation, the artificial increase of conflict in society, radicalisation, and support for anti-system actors, dangers to public security, the undermining of diplomacy, or the acquisition of control over the information networks and information environment. Based on this, current concepts of defence and protection relevant to Europe are discussed.