The concept of national health insurance began in the early 20th century in the United States and then came to prominence during the Truman administration following World War II. Between 1958 and 1964, controversy grew and a bill was drafted. The signing of the act, as part of Johnson's Great Society, began an era with a greater emphasis on public health issues. Medicare and Medicaid became the United States' first public health insurance programs. The legislation was vigorously opposed by the American Medical Association until it had been enacted, following which the AMA cooperated in its implementation.