A historical analysis of the regulation of propaganda and obligations on States to prevent its dissemination reveals competing origins of the protection (and suppression) of free expression in international law. The conflict between the ‘marketplace of ideas’ approach favoured by Western democracies and the Soviet Union's proposed direct control of media outlets have indirectly contributed to both the fake-news crisis and engineered polarisation via computational propaganda. From the troubled League of Nations to the Friendly Relations Declaration of 1970, several international agreements and resolutions limit State use of propaganda to interfere with ‘malicious intent’ in the affairs of another. Yet State and non-State actors continually use a variety of methods to disseminate deceptive content sowing civil discord and damaging democracies in the process. In Europe, much of the discourse about the regulation of ‘fake news’ has revolved around the role of the European Union's General Data Protection Regulation and the role of platforms in preventing ‘online manipulation’. There is also a common perception that human rights frameworks limit States' ability to constrain political speech; however, using the principle of subsidiarity as a mapping tool, a regulatory anomaly is revealed. There is a significant lack of regulatory oversight of actors responsible for, and the flow of, computational propaganda that is disseminated as deceptive political advertising. The article examines whether there is a right to disseminate propaganda within our free expression rights and focuses on the harms associated with the engineered polarisation that is often the objective of a computational propaganda campaign. The article concludes with a discussion of the implications of maintaining this status quo and some suggestions for plugging the regulatory holes identified.