Robert Hale Merriman (1908-1938) was a graduate student in economics at the University of California at Berkeley when he became interested in Russian economics. He had met his future wife Marion Stone when both were undergraduates at the University of Nevada; they married on their graduation day, May 9, 1932. The Merrimans moved to Moscow in January 1935. An excursion to Vienna gave Robert and Marion a firsthand view of Nazism and motivated Robert, who had received some basic military training in ROTC as a undergraduate at the University of Nevada, to join the Abraham Lincoln Brigade in 1937. In Spain, Robert trained other U.S. volunteers and eventually rose to the rank of chief of staff of the 15th International Brigade. At first, Marion remained in Moscow, working for a New York Timescorrespondent Walter Duranty. She came to Spain in March of 1937 to tend to Robert after he was wounded by a gunshot to the shoulder in the Battle of Jarama. After his recovery, Marion remained in Spain and served the brigade as a clerk. Marion also worked in a hospital, held various staff jobs, collected information for death certificates, and led tours for visiting celebrities. She was eventually promoted to the rank of corporal. In November 1937, Marion returned to the United States to raise money for the cause. She made numerous speeches at rallies across the country and returned to San Francisco in March 1938, where she worked as a secretary for a group raising medical aid for the Loyalists.

After Robert Merriman disappeared, during an ambush at Corbera (Ebro Valley), conflicting reports stated that he was being held by fascist forces or that he had been killed. Unsuccessful appeals were made urging the U. S. State Department to press for his release, including a petition from UC Berkeley professors and UC President Robert Gordon Sproul. Merriman's body was never found but by 1938 he was presumed dead.

Marion was eventually remarried, to attorney Emil Wachtel. She had three sons with Wachtel, who died in 1977. She held various jobs throughout her life and continued for many years to be active in the Bay Area Veterans of the Abraham Lincoln Brigade (VALB). She took several trips to Spain after the death of Francisco Franco, and worked strenuously to keep Robert Merriman's memory alive. Later in her life, she co-wrote American Commander in Spain: Robert Hale Merriman and the Abraham Lincoln Brigade(University of Nevada Press, 1986) with journalist and University of Nevada faculty member Warren Lerude. Robert Jordan, the main character in For Whom the Bell Tolls– Ernest Hemingway's Spanish Civil War novel – was apparently modeled after Robert Merriman.