In the roughly quarter-century since then-First Lady Hillary Clinton’s health care plan hit the headlines, advocates of expanded government control have asserted that single-payer systems such as Medicare have far lower administrative costs than private insurance. So moving toward “Medicare for all,” they said, would generate vast sums to increase access to health care. Paul Krugman, for example, argued that ObamaCare administrative cost savings would pay for its expanded coverage.

But the cost claim is alchemy, not actuality.