In December 1935 Masaryk retired from the presidency, and Beneš was elected his successor by an overwhelming majority, including Hlinka's party. A treaty with the Soviet Union in 1935 enhanced the sense of national security. The program of the Communist Party was determined not only by this treaty but also by the general reorientation of the Comintern, which now urged cooperation with antifascist forces in popular fronts. The Czechoslovak communists did not, however, seek cabinet posts. The erection of fortifications along the German frontier modeled on France's Maginot Line was commonly interpreted as an unwritten pledge of the French army to aid Czechoslovakia in the event of an unprovoked attack. Their capture would have given (and later did give) the Germans the key to the French defensive system. In February 1937 Prime Minister Milan Hodza made significant progress toward gaining the cooperation of those segments of the German population that were attached to the principles of democracy. The hope that Czechoslovakia would be able to withstand pressure from Nazi Germany seemed, for a while, to be justified. But, soon after the death of Masaryk, in September 1937, Hitler embarked on his program of eastward expansion. As early as November 1937, he informed his military chiefs of his intention to move against Austria and Czechoslovakia. After the annexation of Austria in March 1938, the Czechoslovak crisis became acute. The Czechoslovak leaders divided their energies. Hodza devoted all his talents to a search for a compromise that would satisfy the Sudeten Germans and held long conferences with Henlein's lieutenants. President Beneš, assisted by his foreign minister, Kamil Krofta, maintained contacts with foreign powers. Henlein played his hand so skillfully that the influential circles, especially in London, believed that he was a free agent and not Hitler's stooge. The advocates of “appeasement,” then rapidly gaining ground in Britain and France, failed to realize that the Sudeten German negotiators had no intention of compromise and acted on instructions from Berlin. The main task of Henlein's party was to give Hitler a better chance to dislocate the republic without recourse to war. To invalidate critical comments from London and Paris, Beneš consented late in July to the mission of Lord Runciman, whose avowed purpose was to observe and report on conditions within the country. The crisis culminated in September 1938. Armed with information supplied by Lord Runciman, the British prime minister Neville Chamberlain visited Hitler at Berchtesgaden and Godesberg.