Dr. Robert Soblen (born Ruvelis Sobolevicius, also known as Roman Well; November 7, 1900 – September 11, 1962), was a prominent member of the pro-Trotsky Left Opposition in Germany in the 1930s. He moved to the United States in 1941 with his brother Jack Soble, and was arrested in 1960 as a Soviet spy. Convicted and sentenced to life in prison, he fled the U.S. while on bail and sought asylum first in Israel, then Britain. He committed suicide by overdosing on barbiturates when his last appeal for asylum in Britain was denied.
Born in Vilkaviskis, Lithuania, both Soblen and his younger brother Jack (born Abromas Sobolevicius, also known as Abraham or Adolph Senin), were important figures in Trotskyist circles in the 1920s and 1930s. They were very active in French and German Trotskyist movements, handling both Trotsky's secret correspondence to the Soviet Union and publication of his Opposition Bulletin. Jack Soble later claimed he and Robert began working for the Soviet Secret Police against Trotsky in 1931. In 1932, Trotsky broke with the brothers, and Robert joined Trotsky's enemies in the Communist Party of Germany.