Critics of the Affordable Care Act continue to insist that the American health care system, as presently constructed, is the best in the world. But most of the available evidence suggests otherwise. And now there's yet one more set of data making the same point. It comes from a study supported by the Commonwealth Fund, which specializes in comparisons of health care across country. And it looks at a statistic called "Mortality Amenable to Health Care." As the name suggests, it measures preventable deaths, which is a pretty good proxy for the quality of a nation's health care system.