Abstract
This article attempts to look at practical examples approximation of political, economic and military Germany and Soviet Russia, then the Soviet Union in 1921–1930. It is adopted the thesis according to which the German-Soviet political, economic and military rapprochement during the years 1921–1930 significantly endangers the safety of the Second Republic of Poland.To prove this thesis it was decided to rely on both the literature and source materials, including first of all materials in the Central Military Archives in Warsaw-Rembertów. The key is turned out to be the materials collected in teams of Division II of the Supreme Command of the Polish Army and the Russian Collection Act. The collected archival documents pinpoint various areas of cooperation with the Germans and the Soviets during the given period, as well as determine to what extent the Polish military intelligence assessed the feasibility and effects of the approximation to a direct threat to the security of the Polish state.The content allows concluding that the Polish military intelligence had good diagnosis examples of German-Soviet cooperation, often with a strong anti-Polish shape and character. This cooperation in the years 1921–1930 was particularly intense, threatening the security interests of the Second Republic of Poland and leading to the negation established after the Treaty of Versailles and the Treaty of Riga Polish borders on both the west and the east.