The tension between freedom of expression and the protection of national security is a timeless research problem. Based on the specific historical moment and international political and security situation for Europe in general and the Three Seas region specifically, the aim of this article will be a normative assessment of the appropriate approach to potential limitations on online freedom of expression considering national security. The starting point will be an overview of the state of the art of the European Court of Human Rights practice. Then, the analytical framework of Berlin’s two concepts of liberty will be utilised to differentiate between laissez-faire approaches connected to the first paragraph of Article 10 and the limitations, which are necessary in a democratic society per the second paragraph of Article 10 of the European Convention on the Human Rights and Fundamental Freedoms. In a novel approach to the problem at hand, the main research hypotheses that are subject to analysis are that there is a need for a more nuanced approach to balancing online freedom of expression and national security and that Berlin’s two concepts of liberty, when connected to Finnis’s basic goods, can be a useful normative framework in this regard. The need to differentiate between values and facts while recognising the incommensurability of values will be considered.