The policy of collective security in its multilateral (the League of Nations) and bilateral forms was put to the test by growing Nazi aggression and instability in Europe. In March of 1936 Germany remilitarized the Rhineland in violation of the Locarno Treaty (1925). The League of Nations and Western powers failed to either act with conviction or intervene militarily. The Spanish Civil War (1936-1939), in which Germany and Italy decisively intervened, accelerated the disintegration of the collective security in Europe. The Soviets, initially maintaining an official policy of noninterference, acted cautiously. Seeing that Paris and London's neutral stand in fact did nothing about German and Italian actions in Spain, however, the Soviet Union began limited intervention in Spain to help the loyalists. These developments undermined the Franco-Soviet alliance and caused growing Soviet disillusionment about collective security.
In March 1938, immediately after the Anschluss (union) of Germany and Austria and despite Western passivity, Litvinov declared the Soviet Union's readiness to begin discussions with other powers about practical measures to punish the aggressors. Again, Britain and France, hoping to appease German leader Adolf Hitler, failed to respond to the Soviet initiative.
Throughout the Czechoslovak (Sudeten) Crisis (1938) the Soviet government repeatedly affirmed its willingness to support all decisions and recommendations of the League of Nations to combat aggression and preserve peace, irrespective of whether these decisions coincided with the Soviet immediate national interests. The Soviets declared their readiness to come to the aid of Czechoslovakia, provided France did likewise. But France and Britain ignored the Soviet Union and tried to come to peaceful terms with Hitler at Czechoslovakia's expense. Despite the fact that the French refusal to help Czechoslovakia against Germany had formally freed the U.S.S.R. from the obligation to render aid to Prague, the Soviets were ready to provide military support to the Czechs if their government wished it. The Czechoslovak government, however, opted to concede to the German-British- French ultimatum adopted in Munich about the settlement of the crisis, and ceded the Sudetenland to Germany.
The question of whether the Soviet Union was really ready to provide Czechoslovakia with effective military support remains a matter of controversy. On one hand, many Western observers pointed out that the Red Army, particularly in the aftermath of the Great Purge (1930s), was in no condition to operate against a powerful foe beyond the Soviet borders, while neither Poland nor Romania (the U.S.S.R.'s immediate neighbors) was prepared to accept Soviet troops on their way to Czechoslovakia. On the other hand, many critics of official British and French policy at the time, such as Winston Churchill and Joseph Paul-Boncour, insisted that unique opportunities to stop the Nazis were lost when the Soviet offers of cooperation were rebuffed. Moreover, in 1938, before Munich, most German generals expected that a simultaneous war with Britain, France, the Soviet Union, and Czechoslovakia would be a disaster. For sure, Soviet military aid to Czechoslovakia would have been indirect but still a potent strategic factor in the situation. Thus, during the Sudeten Crisis the Soviet Union proved to be the only country that kept faith with its international obligations in relations with Czechoslovakia and collective security in Europe.
Moscow drew the worst possible conclusions from Munich. The Soviets found out that the shortsighted Western democracies ignored the Soviet offer to help them and accepted Czechoslovakia's dismemberment by Germany. With the evident failure of the collective security policy to halt German aggression, Stalin removed Litvinov from the Foreign Ministry and ended the pro-Western policy identified with him. The Soviets again changed their foreign policy course and became amenable to approaches from Berlin. This shift culminated in the Soviet-Nazi Pact of August 1939. When Britain and France went to war against Germany the following month, the Soviet Union was already a virtual ally of the latter.
During the 1930s the Soviet Union was a determined champion of collective security and a reliable partner for a possible alliance against Nazi Germany. Western Europe's resistance to forming a firm alliance with the Soviet Union was indeed an irresponsible and ill-considered rejection of a viable strategic option. It should be noted also that many misunderstandings rooted in the past, continued suspicions and antagonisms, and mutual ideological hostility precluded politically necessary adjustments between the U.S.S.R. and the Western democracies and undermined long-term and stable security cooperation between Moscow and the West. The failure of collective security was to bring tragedy to the Soviet Union and to all Europe.
-- Peter Rainow, San Mateo, California