Social Security has become a topic of national conversation; politicians and news media are widely discussing the need for, and possible shape of, Social Security reform. The basic factors leading to the necessity of policy change are evident: fertility has gradually declined and longevity increased; thus, the number of older Americans relative to those of working age has risen, and these trends render a pay-as-you-go pension system unable to continue to deliver benefits at previous levels of generosity without additional revenues. This brief first attempts to survey the backdrop of the present economic situation more broadly than just demographics. After setting a context in that way, it suggests a two—part answer to the question in its title. Finally, it briefly discusses the relation of one frequently mentioned possible reform, the introduction of personal accounts, to Social Security’s current difficulties.