The estimated 10-year cost (2010-2019) of expanding health insurance coverage is at least $1 trillion. New revenue sources will not cover this cost. Thus, to make such coverage affordable, it is necessary to "bend the cost curve" in the rate of annual increases in health care spending, which in most years has significantly exceeded the overall rate of inflation. This will require addressing the underlying determinants: primarily the behavior of patients, hospitals, and physicians as they use available technologies and treatments.