Members of the American Society for Microbiology (ASM) have a considerable history of bringing scientific and technical knowledge to the issue of biological weapons control and being available to serve in advisory roles to the government. ASM's involvement with the biological weapons issue began in the 1940s, when microbiologists served as advisors to the government's Biological Defense Research Program and participated in the Biological Warfare Committee of the U.S. National Academy of Sciences. In 1970, a controversy resulting from the ASM's involvement with this issue abated when the ASM Council approved a statement concerning non-secrecy and free movement in research. Simultaneously, the society affirmed support for President Richard M. Nixon's action to end the U.S.'s offensive biological weapons program. The society's code of ethics, published in 1985, contains two relevant sections that seek to discourage ASM members from participating in biological weapons development.