Even with the newfound power of the SdP, gained with the help of the Nazis, Henlein did not become a declared follower of Adolf Hitler until 1937; after the pro-German camp within the SdP represented by Karl Hermann Frank emerged victorious. Newer research shows his position within the SdP became very difficult, when in October 1937 the Czechoslovak authorities were tipped off (possibly by the German secret service) about the homosexuality of Heinz Rutha, one of his closest allies, who was imprisoned on charges that he had sexual relations with young men who were active in the SdP. Rutha hanged himself in a jail cell awaiting trial. Henlein then swiftly aligned himself with the slogan "Ein Volk, ein Reich, ein Führer!" ("One People, One Country, One Leader!"), thus calling for the predominantly (typically more than 80%) German-speaking Sudetenland to be a part of Germany. Unknown to Henlein, on 5 November 1937 at the conference in Berlin recorded in the Hossbach memorandum, Hitler declared that he was planning to attack Austria and Czechoslovakia in the very near-future. The British historian Richard Overy noted in the Hossbach memorandum that Hitler said nothing about Czechoslovakia's treatment of the Sudeten Germans as a reason for war, instead giving the reasons that Germany was falling behind in the arms race with Britain and France, and so needed to conquer Czechoslovakia to exploit its resources, industries and people to gain the lead in the arms race and to provide for economic autarky to make Germany immune to a British blockade.