<P> For Germany, because an autarkic economic approach or an alliance with Britain were impossible, closer relations with the Soviet Union to obtain raw materials became necessary, if not just for economic reasons alone . Moreover, an expected British blockade in the event of war would create massive shortages for Germany in a number of key raw materials . After the Munich agreement, the resulting increase in German military supply needs and Soviet demands for military machinery, talks between the two countries occurred from late 1938 to March 1939 . The third Soviet Five Year Plan required new infusions of technology and industrial equipment . German war planners had estimated serious shortfalls of raw materials if Germany entered a war without Soviet supply . </P> <P> On 31 March 1939, in response to Nazi Germany's defiance of the Munich Agreement and occupation of Czechoslovakia, Great Britain pledged its support and that of France to guarantee the independence of Poland, Belgium, Romania, Greece, and Turkey . On 6 April Poland and Britain agreed to formalize the guarantee as a military alliance, pending negotiations . On 28 April, Hitler denounced the 1934 German--Polish Non-Aggression Pact and the 1935 Anglo - German Naval Agreement . </P> <P> Starting in mid-March 1939, in attempts to contain Hitler's expansionism, the Soviet Union, Britain and France traded a flurry of suggestions and counterplans regarding a potential political and military agreement . Although informal consultations commenced in April, the main negotiations began only in May . At the same time, throughout early 1939, Germany had secretly hinted to Soviet diplomats that it could offer better terms for a political agreement than Britain and France . </P> <P> The Soviet Union, which feared Western powers and the possibility of "capitalist encirclements", had little faith either that war could be avoided, or faith in the Polish army, and wanted nothing less than an ironclad military alliance with France and Britain that would provide a guaranteed support for a two - pronged attack on Germany; thus, Stalin's adherence to the collective security line was purely conditional . Britain and France believed that war could still be avoided, and that the Soviet Union, weakened by the Great Purge, could not be a main military participant, a point that many military sources were at variance with, especially given the Soviet victories over the Japanese Kwantung Army on the Manchurian frontier . France was more anxious to find an agreement with the USSR than was Britain; as a continental power, it was more willing to make concessions and more fearful of the dangers of an agreement between the USSR and Germany . These contrasting attitudes partly explain why the USSR has often been charged with playing a double game in 1939: carrying on open negotiations for an alliance with Britain and France while secretly considering propositions from Germany . </P>

How did the great depression and the german soviet nonaggression pact lead to ww2