THE UNITED STATES boasts the most advanced medical care in the world. American physicians routinely transplant organs and create babies in test tubes and are more successful at treating cancer and other serious illnesses than physicians in any other nation. Wealthy foreigners often seek treatment in the United States, knowing that they will receive the best medicine money can buy.

Most Americans receive adequate, even excellent, health care in this system. These are the insured Americans—those whose companies provide health care benefits or those who can afford private health care policies. These citizens often receive preventive care through regular examinations and they feel confident that, should they become seriously ill, they will be treated and the bulk of the costs will be covered by insurance.

Unfortunately, more than 37 million Americans remain uninsured. They may be employees of the one-fourth of companies that do not provide health...