Respuesta :

Answer:

After first having cooperated with Germany in invading Poland whilst remaining neutral in the Allied-Axis conflict, the Soviet Union perforce joined the Allies in June 1941 after being invaded by Germany.

Explanation:

(Wikipedia)

Answer:

Germany broke the German-Soviet Nonagression Pact.

Explanation:

This event led to the Soviet Union joining the side of the Allies during World War II