THE U.S. SUPREME COURT will release its ruling on the Patient Protection and Affordable Care Act any day now. But regardless of how the court rules, the U.S. health care delivery system must change. Its current flight path has one conceivable outcome: crash.

That's the conclusion of health care experts from across the spectrum. The numbers tell the story: In 2010, the Unites States spent $2.6 trillion on health care, 17.9 percent of the nation's gross domestic product. That's 10 times the amount spent in 1980. On this trajectory, by 2050 some 40 percent of the GDP will be consumed by health care, leaving little for investment, innovation, and other society-boosting purposes. What's more, the U.S. spends much more per capita on health care than other industrialized countries. Our $7,538 compares with Norway's $5,003, Canada's $4,079, and Japan's $2,729.

Despite this outlay, patient outcomes are not necessarily better--although the standard laments about infant mortality and life expectancy at birth should be taken with a grain of salt. David Hogberg, writing for the National Center for Public Policy Research, points out that there are "inconsistent standards" across nations for measuring infant mortality: The U.S. considers any baby with any sign of life to be a "live birth," while other nations look at gestational age or some other criterion. In Switzerland, for example, "a baby must be at least 30 centimeters long at birth to be counted as living." And life expectancy does not strongly correlate to health care spending. Spain, for example, has a higher ranking in life expectancy than 10 other nations that spend more. Looking at five-year survival rates for illnesses such as cancer and heart disease may be more apt; there, the United States does well.

But who or what is to blame for soaring costs? Fingers point in all directions: Some experts blame technology, readily available and quite possibly overused thanks in part to medical malpractice torts. Others identify the under-use of primary-care doctors and the overuse of specialists. Still others indict a fragmented system of providers and third-party payers that prevents market forces from countering rising costs. Finally, Americans have a higher prevalence of chronic disease than residents of other industrialized countries, either because we are more sick or because we detect disease more readily.