Healthcare rationing refers to limiting the availability of some medical care for certain populations (or all populations, depending on the efficacy of the procedure in question), with the payer in charge of setting the rules. The threat of rationing has long been one of the most powerful arguments leveled against proposals for an expanded government control of the U.S. health care system. Critics of such expanded control argue that in order to control costs in a revamped system (particularly if we were to switch to a single-payer system in which the government pays for everyone’s care) the government would have to restrict – ie, ration – care, by refusing to pay for certain procedures or medication or by putting limits on care for the elderly or terminally ill. Some proponents of increased government control argue that healthcare is already, in effect, rationed in the United States, as consumers are limited in their ability to get adequate health insurance – and health care – by rapidly climbing health care costs. Those who do not have health insurance, as well as those who face unrealistic out-of-pocket costs, are essentially unable to obtain care. In addition, health insurers and government health care programs (Medicare and Medicaid) already ration care to some extent, via pre-authorization requirements, limited networks, limited formularies, and rules like step therapy for prescription drug coverage.