In 1938, at the government-convened National Health Conference, organized labor emerged as a major proponent of legislation to guarantee universal health care in the United States. The American Medical Association, representing physicians' interests, argued for preserving physicians' free-market prerogatives. Labor activists countered these arguments by insisting that health care was a fundamental right that should be guaranteed by government programs.

    The labor activists' position represented a departure from the voluntarist view held until 1935 by leaders of the American Federation of labor (AFL), a leading affiliation of labor unions; the voluntarist view stressed workers' right to freedom from government intrusions into their lives and represented national health insurance as a threat to workers' privacy. AFL president Samuel Gompers, presuming to speak for all workers, had positioned the AFL as a leading opponent of the proposals for national health insurance that were advocated beginning in 1915 by the American Association for Labor Legislation (AALL), an organization dedicated to the study and reform of labor laws. Gompers' opposition to national health insurance was partly principled, arising from the premise that governments under capitalism invariably served employers', not workers', interests. Gompers feared the probing of government bureaucrats into workers' lives, as well as the possibility that government-mandated health insurance, financed in part by employers, could permit companies to require employee medical examinations that might be used to discharge disabled workers.

    Yet the AFL's voluntarism had accommodated certain exceptions: the AFL had supported government intervention on behalf of injured workers and child laborers. AFL officials drew the line at national health insurance, however, partly out of concern for their own power. The fact that AFL outsiders such as the AALL had taken the most prominent advocacy roles antagonized Gompers. That this reform threatened unionsponsored benefit programs championed by Gompers made national health insurance even more objectionable. Indeed, the AFL leadership did face serious organizational divisions. Many unionists, recognizing that union-run health programs covered only a small fraction of union members and that unions represented only a fraction of the nation's workforce, worked to enact compulsory health insurance in their state legislatures. This activism and the views underlying it came to prevail in the United States labor movement and in 1935 the AFL unequivocally reversed its position on health legislation.