When I asked historians if they could think of any similar undoing of an existing part of the social safety net, several said they could not. The court blocked parts of President Franklin D. Roosevelt’s New Deal, but never dismantled such a large program already underway. The best-known piece of health care law to be repealed by Congress — a 1988 law expanding catastrophic coverage in Medicare — was far narrower than the Affordable Care Act. It was also only starting to go into effect when Congress undid it, in 1989.
Julian Zelizer, a Princeton historian and the author of a new book on the 1960s expansion of the safety net, said the closest analogy might be Reconstruction and the reaction to it. An enormous federal effort initially succeeded in expanding civil rights in the South, only to be reversed in later years. The reversal lasted decades.