The precise function that Marxist-Leninist ideology serves in the formation and conduct of Soviet foreign policy remains a highly contentious question among Western scholars. In the first postwar year, however, few senior officials or Soviet specialists in the West doubted that Communist ideology served as the constitutive element of Soviet foreign policy. Indeed, the militant revival of Marxism-Leninism after the Kremlin had downplayed it during 'The Great Patriotic War" proved to be an important factor in the complex of causes that led to the breakup of the Grand Alliance. Moscow's revival of that ideology in 1945 prompted numerous top-level Western leaders and observers to regard it as heralding a new wave of Soviet world-revolutionary messianism and expansionism. Many American and British officials were even alarmed by the claim, renewed, for example, in Moscow's official History of Diplomacy, that Soviet diplomacy possessed a "scientific theory," a "weapon" possessed by none of its rivals or opponents. This "weapon," Marxism-Leninism, Moscow ominously boasted, enabled Soviet leaders to comprehend, foresee, and master the course of international affairs, smoothing the way for Soviet diplomacy to make exceptional gains since 1917. Now, in the postwar period, Stalinist diplomacy opened before the Soviet Union "boundlesshorizons and the most majestic prospects."
Stalin, the Politburo, and the Onset of the Cold War, 1945-1946