Death is inevitable, but not disease. Bacteria and viruses are no mean adversaries, nor are they easily defeated. (46) If we fail to be watchful or to protect those most at risk, a public-health catastrophe is inevitable, and yet somewhere within the span of the last thirty years the idea of the common good has disappeared from our national consciousness, giving way to the misconception that we no longer need concern ourselves with the welfare of our fellow citizens. It is a dangerous conceit, and it leads us toward a future infected with unprecedented and unnecessary disease. A public-health system is only as strong as its weakest link; an epidemic enforces, in the most rigorous fashion, the American credo that all men are created equal. (47) If we allow one segment of our society to suffer and perish from preventable diseases, little stands in the way of collective doom. Yet today, 44 million people in the United States are without health insurance; those who can afford to pay for it generally receive inferior treatment, despite the fact that Americans spend $1.4 trillion annually for their health care. Prevention becomes secondary to simply keeping people alive. (48) We must not simply concern ourselves with the state of American public health; as distances collapse and human populations grow ever more mobile, so also new and deadly diseases find their way across deserts and oceans. Ironically, the medical revolutions of the twentieth century have contributed to our over-confident neglect of the public-health infrastructure. (49) We spend vast sums to lengthen the lives of terminally ill patients by a few days and refuse to make modest investments that would prevent millions of needless illnesses and death. The Americans we know pay too much for their health care, and compared with other countries we receive a very poor return on our investment. The reason are many, but they are not hard to understand: in essence, we have tended historically to view health care as a commodity like any other. But health is not a product; it is a public good. The evidence is clear even when viewed through the reductive lens of purely economic self-interest, market-based medicine is a failure. Healing people after they fall ill is vastly more expensive than preventing the illness in the first place. (50) Yet policymakers have consistently preferred the most expensive and least efficient models of health care, proving once again that the supporters of privatization are motivated not by practical economics but by an ideology that is little more than a mask concealing the most irrational self-interest.