This article focuses on the Central and Eastern European in the process of shaping their security relations. The aim of the paper is to present and analyze the evolution of security relations in the region under the aegis of the EU, NATO and the Organization for Security and Co-operation in Europe (OSCE). The interplay of the institutions shows that the EU is not a single power in the European security system thus the maintenance of stable and peaceful relations depend mostly on cooperation between a number of institutions and groupings. The EU and NATO’ s role was central due to their policies of enlargement and the stabilization effects on third partner countries. The OSCE with its well promising position in Europe has been weaken due to decline of interests of major power states and its functions performed simultaneously by the EU and NATO. Both organizations have taken to a large extent the place of the OSCE.

The subject of the article is the importance of the United States in Poland’s military security policy in relation to the war in Ukraine. The article begins with an introduction discussing its main assumptions and a synthetic historical background of the importance of the US for Poland and its security. The main part of the article is divided into two parts, the first one discussing the importance of the US in Poland’s military security policy after the Cold War. The second part is devoted to the change in the importance of the US in this policy in connection with the outbreak of the war in Ukraine and the main factors that determine this change. The aim of the article is to identify and analyze the changes in the importance of the United States in the Polish military security policy as a result of the outbreak of the war in Ukraine in 2022. The main research problem is whether the importance of the US in Poland’s military security policy increased as a result of the war, and if so, because of what main factors? The thesis of the article states that the war in Ukraine increased the importance of the US as the main external guarantor of Poland’s security and defense. This is due to the leading role played by the United States in military support for Ukraine and strengthening NATO’s eastern flank, including Poland, in the absence of leadership from Western European powers. The research included interviews with scientists and analysts from research centers in Washington and New York.