In 1953, he was elected to the Forsyth City Council. Finding a liking and a talent for public service, he won a string of elections, and served as Forsyth’s mayor from 1955 to 1961, as a member of the Montana House of Representatives from Rosebud County from 1961 to 1963, and as a state senator in Helena, the capital, from 1963 to 1967.
He then returned to the lower house for two years, but with encouragement from Democratic and legislative colleagues he had his sights set on the national stage. He was a square-jawed, down-to-earth politician whose interests in animals and agriculture grew out of long associations with farmers, ranchers and small-town people in sparsely populated eastern Montana.
Dr. Melcher lost his initial race for a seat in Congress in 1966. But in 1969 he won a special election to replace Representative James F. Battin, a Republican who had resigned to take a federal judgeship.
Dr. Melcher settled in Missoula after his years in Washington. He founded a lobbying and consulting firm and worked for the Association of American Veterinary Medical Colleges and for various veterinary medical groups for many years.
In an interview for this obituary in 2017, Dr. Melcher recalled his 1984 amendment to the Animal Welfare Act of 1966, requiring that the psychological well-being of nonhuman primates be considered in research.
“It was just something I could do,” he said of his measure, which prohibited long periods of isolation in cages and other mental cruelties.
Jane Goodall, the primatologist and authority on chimpanzees, hailed his amendment. She visited Dr. Melcher in Washington, gave him a copy of her book, “The Chimpanzees of Gombe” (1986), and wrote in an inscription: “When this bill is well and truly implemented, the difference in the lives of hundreds of animals will truly be great.”