Moss was elected to a second term in 1964, defeating Brigham Young University President Ernest L. Wilkinson. He was elected to a third term in 1970 defeating four-term Congressman Laurence J. Burton. He gained national prominence with regard to environmental, consumer, and health care issues. Moss became an expert on water issues and wrote "The Water Crisis" in 1967. He worked to secure additional national parks for Utah and started important investigations into the care of the elderly in nursing and retirement homes, and into physicians' abuses of the federal Medicaid program. In 1974, Moss joined Senator Frank Church (D-Idaho) to sponsor the first legislation to provide federal funding for hospice care programs. The bill did not have widespread support and was not brought to a vote. Congress finally included a Hospice benefit in Medicare in 1982. In 1976 Moss backed a constitutional amendment overturning Roe v. Wade and outlawing abortion.