Union's attempts to seek closer political ties to Germany along with an additional credit agreement. Litvinov's strategy faced ideological and political obstacles. The ruling Conservatives in Britain, who dominated the House of Commons from 1931 onwards, continued to regard the Soviet Union as no less of a threat than Nazi Germany (some saw the USSR as the greater threat). At the same time, as the Soviet Union underwent upheavals in the midst of the Great Purge of 1934–1940, the West did not perceive it as a potentially valuable ally. Further complicating matters, the purge of the People's Commissariat for Foreign Affairs forced the Soviet Union to close down quite a number of embassies abroad. At the same time, the purges made the signing of an economic deal with Germany less likely: they disrupted the already confused Soviet administrative structure necessary for negotiations and thus prompted Hitler to regard the Soviets as militarily weak. Spanish Civil War The Nationalists led by General Francisco Franco defeated the Republican government for control of Spain in a very bloody civil war, 1936–1939. Germany sent in elite air and tank units to the Nationalist forces; and Italy sent in several combat divisions. The Soviet Union sent military and political advisors, and sold munitions in support of the "Loyalist," or Republican, side. The Comnitern helped Communist parties around the world send in volunteers to the International Brigades that fought for the Loyalists. The other major powers were neutral. Collective security failures Litvinov's policy of containing Germany via collective security failed utterly with the conclusion of the Munich Agreement on September 29, 1938, when Britain and France favored self-determination of the Sudetenland Germans over Czechoslovakia's territorial integrity, disregarding the Soviet position. However, it is still disputed whether, even before Munich, the Soviet Union would actually have fulfilled its guarantees to Czechoslovakia, in the case of an actual German invasion resisted by France. In April 1939, Litvinov launched the tripartite alliance negotiations with the new British and French ambassadors, (William Seeds, assisted by William Strang, and Paul-Emile Naggiar), in an attempt to contain Germany. However, they were constantly dragged out and proceeded with major delays. The Western powers believed that war could still be avoided and the USSR, much weakened by the purges, could not act as a main military participant. The USSR more or less disagreed with them on both issues, approaching the negotiations with caution because