Walter Scheel, who as foreign minister and deputy chancellor of West Germany under Chancellor Willy Brandt from 1969 to 1974 helped foster detente with the Soviet bloc and rapprochement with communist East Germany, died Wednesday in Bad Krozingen, in southwest Germany. The reunification of Germany in 1990, the collapse of the Soviet Union and the end of the Cold War followed a long process of Soviet political and economic stagnation and corresponding declines in Soviet influence over European satellites it acquired at the end of World War II. [...] historians say Ostpolitik played a crucial role as an early catalyst, letting West and East step back from destructive confrontations. In a cutaway coat for special occasions or a turtleneck for cocktail parties, he looked every inch the diplomat: a distinguished face, affable and conciliatory; an easy smile for a telling joke, receding gray hair that curled fashionably over his collar at the back. [...] in May 1974, Brandt was forced to resign when Guenter Guillaume, a senior member of his staff, was arrested and exposed as an agent of the East German secret service, the Stasi. Mr.