Munson's practice was illegal prior to the Roe vs. WadeU.S. Supreme Court decision in 1973. Until his retirement in 1986, he was the only physician in South Dakota to perform abortions.
Munson opened his practice in 1967. He was arrested in 1969 after performing an abortion on a 19-year-old patient. Munson challenged his conviction, winning in circuit court. The state appealed, and the South Dakota Supreme Court ruled against him. He appealed this decision, which was rendered moot by Roe.