Union of Soviet Socialist Republics: World War II

On Aug. 23, 1939, the USSR concluded a nonaggression pact with Nazi Germany, which shortly afterward invaded Poland, precipitating World War II. Soviet troops also entered (Sept., 1939) Poland, which was divided between Germany and the USSR. Lithuania, Latvia, and Estonia were occupied (1940) by the Soviet Union, and in mid-1940 were transformed into constituent republics of the USSR. Finland opposed Soviet demands, and the Finnish-Russian War of 1939–40 resulted; it ended in a hard-earned Soviet victory. Finland ceded territory, which was organized into the Karelo-Finnish SSR (which in 1956 became part of the RSFSR as the Karelian Autonomous Soviet Socialist Republic). Romania was forced (1940) to cede Bessarabia and N Bukovina, and the Moldavian SSR was created. In Apr., 1941, a nonaggression treaty with Japan was signed.

Although defense preparations were accelerated (probably in anticipation of eventual war with Germany), when Germany attacked on June 22, 1941, the Soviet Union was caught by surprise. Romania, Finland, Hungary, Slovakia, and Italy joined in the invasion of the USSR. By the end of 1941 the Germans had overrun Belorussia and most of Ukraine, had surrounded Leningrad (St. Petersburg), and were converging on Moscow. The success of this first German offensive was in part due to the 1935–39 purges of the army and the party, which had robbed the USSR of many of its best military minds and political organizers.

A Soviet counter-offensive saved Moscow, but in June, 1942, the Germans launched a new drive directed against Stalingrad (now called Volgograd) and the Caucasus petroleum fields. Stalingrad held out, and the surrender (Feb. 2, 1943) of 330,000 Axis troops there marked a turning point in the war. The Soviets drove the invaders back in an almost uninterrupted offensive and in 1944 entered Poland and the Balkan Peninsula. Early in 1945, German resistance in Hungary was overcome, and Soviet troops marched into East Prussia. The converging Soviet armies then closed in on Berlin in a climactic drive. On May 2, 1945, Berlin fell; on May 7 the USSR together with the Western Allies accepted the surrender of Germany.

The Soviet victory was obtained at the great price of at least 20 million lives (including civilian casualties) and staggering material losses. The United States contributed much aid, about $9 billion, to the USSR through lend-lease. Understandings concerning the conduct of war and postwar policies had been reached by the USSR, the United States, and Great Britain at the Moscow Conferences (1941–47), the Tehran Conference (1943), the Yalta Conference (1945), and the Potsdam Conference (1945).

In accordance with a previous agreement, the Soviet Union declared war on Japan on Aug. 8, 1945, two days after the United States dropped an atomic bomb on Hiroshima. A swift campaign brought Soviet forces deep into Manchuria and Korea by the date (Sept. 2, 1945) Japan surrendered. As a direct result of the war, the USSR received the southern half of Sakhalin Island and the Kuril Islands from Japan; the northern part of East Prussia from Germany; and some additional territory from Finland. By agreements in 1945 with Poland and Czechoslovakia the USSR also vastly increased the area of the Belorussian and Ukrainian republics.

Sections in this article:

• Introduction
• Dissolution of the Union
• Glasnost and Perestroika
• The Gorbachev Era
• Détente Ends
• The Era of Détente
• Foreign Relations under Brezhnev
• Domestic Policy under Brezhnev
• The Brezhnev Era
• The Cuban Missile Crisis
• Foreign Relations under Khrushchev
• Domestic Policy under Khrushchev
• The Khrushchev Era
• The Cold War
• World War II
• Pre–World War II Foreign Relations
• Conservatism and Purges
• The First Five-Year Plan
• The Stalin Era
• Early Years
• Bibliography

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