In 1937, Ruebhausen joined the law firm Debevoise, Stevenson, Plimpton & Page, a precursor to the modern firm of
Debevoise & Plimpton. Ruebhausen was exempted from military service during
World War II for health reasons, but in 1941 he moved to
Washington, D.C. to work for the
Lend-Lease Administration financing material aid for the Allied war effort in
Europe. In 1944, he became general counsel to the
Office of Scientific Research and Development (OSRD), headed by the engineer
Vannevar Bush. That year, at the request of President
Franklin D. Roosevelt, Ruebhausen helped Bush draft a letter on how scientific research could be useful to the
United States in peacetime. The letter became the blueprint for the establishment of the
National Science Foundation in 1950. After the war, Ruebhausen returned to practice at Debevoise & Plimpton, where he remained until his retirement in 1987. From 1950 to 1951, he also served as counsel to the International Development Advisory Board, where he began a lifelong relationship with
Nelson A. Rockefeller, the organization's chairman, as a friend and political adviser. When Rockefeller became
Governor of New York, Ruebhausen served him in a number of capacities, including as chairman of a Task Force on Protection from Radioactive Fallout, as Special Adviser on Atomic Energy, and as chairman of a panel on Insurance Holding Companies. Ruebhausen also maintained a long relationship with the
New York City Bar Association, where he served as president from 1980 to 1982. In keeping with his professional interest in science, he served as chairman of the Association's Special Committee on Atomic Energy from 1949 to 1959 and as chair of the Committee on Science and the Law from 1959 to 1967. ==Personal life and death==