The United States spends more than twice as much on health care as the average of other developed nations, all of which boast universal coverage. Yet more than 41 million Americans have no health insurance. Many more are underinsured. Confronted by the rising costs and capabilities of modern medicine, other nations have chosen national health insurance (NHI). The United States alone treats health care as a commodity distributed according to the ability to pay, rather than as a social service to be distributed according to medical need. In this market-driven system, insurers and providers compete not so much by increasing quality or lowering costs, but by avoiding unprofitable patients and shifting costs back to patients or to other payers. This creates the paradox of a health care system based on avoiding the sick. It generates huge administrative costs that, along with profits, divert resources from clinical care to the demands of business. In addition, burgeoning satellite businesses, such as consulting firms and marketing companies, consume an increasing fraction of the health care dollar. We endorse a fundamental change in US health care--the creation of an NHI program. Such a program, which in essence would be an expanded and improved version of traditional Medicare, would cover every American for all necessary medical care. An NHI program would save at least 200 billion dollars annually (more than enough to cover all of the uninsured) by eliminating the high overhead and profits of the private, investor-owned insurance industry and reducing spending for marketing and other satellite services. Physicians and hospitals would be freed from the concomitant burdens and expenses of paperwork created by having to deal with multiple insurers with different rules, often designed to avoid payment. National health insurance would make it possible to set and enforce overall spending limits for the health care system, slowing cost growth over the long run. An NHI program is the only affordable option for universal, comprehensive coverage.