Nowadays, three Baltic countries – Estonia, Latvia and Lithuania – form the most solid core in the camp of European Atlanticists with a strong emphasis on the U.S. as the main security guarantee. Due to their geographical location, they have always been particularly acutely aware of the tension between East and West. With the beginning of Russia’s special military operation on the territory of Ukraine, the topic of a potential Russian threat has become predominant in their foreign policy discourse. The article is devoted to the analysis of the evolution of the Baltic countries’ approaches to national and regional security and the main factors influencing the formation of these approaches, in particular, the relationship between Atlanticism and Europeanism. Particular attention is paid to the existing dichotomy of the Baltic countries in the field of European security, the catalyst of which was the European Union’s course on strategic autonomy. From the very beginning, the idea of strategic autonomy of the European Union did not arouse much enthusiasm in these countries because of the fear of breaking the strategic link between Europe and the United States. The course of the EU leadership towards strategic autonomy has violated the established picture of the world in the Baltic States: NATO, under the strong leadership of the United States, should provide collective defense against a potential Russian threat, and the EU – economic well-being and prosperity. The European Union was assigned a subsidiary and far from the main role in the field of security. However, being part of the EU, the Baltic States could no longer completely ignore the integration projects of Brussels in the field of European defense. If until February 24, 2022, the security policy of the Baltic countries was distinguished by balancing between the United States/NATO and the European Union, then the Ukrainian conflict has once again tipped the scales in favor of the Atlantic choice as the main guarantor of security.