Americans believe that their health system is the best in the world, but in fact it is not. According to the Commonwealth Fund, many countries achieve superior health quality at much lower cost than paid by Americans. A detailed study of the United States and England in the American Journal of Epidemiology in 2011 found that over a lifetime the English have better health than Americans at a fraction of the cost.

The one area where the United States tops all other countries in terms of health is cost. According to the Organization for Economic Cooperation and Development, the United States spent more than any other country – 17.4 percent of gross domestic product on health in 2009, 8.3 percent through government programs such as Medicare and 9.1 percent privately. By contrast, Britain spent only 9.8 percent of G.D.P. on health, 8.2 percent publicly and 1.6 privately.

Thus, for no more than the United States already spends through government, we could have a national health-insurance system equal to that in Britain. The 7.6 percent of G.D.P. difference between American and British total health spending is about equal to the revenue raised by the Social Security tax. So, in effect, having a single-payer health system like Britain’s could theoretically give Americans 7.6 percent of G.D.P. to spend on something else – equivalent to abolishing the payroll tax.

This is a powerful conservative argument for national health insurance.