Since 1950, the federal government of the United States has provided income support by welfare or social insurance mechanisms to individuals with work disabilities unrelated to military service. Currently, the Social Security Administration operates two programs for the disabled: Social Security Disability Insurance (DI) and Supplemental Security Income (SSI). The differences between them reflect a fundamental schism in the American welfare state, which is divided into "tracks" along the line of labor force attachment. As it name implies, DI is an "insurance-like" program: Workers make payroll deductions that over time qualify them for benefits based on average lifetime earnings should they ever become disabled. SSI, on the other hand, is a "welfare" program designed for individuals with little history of employment and few resources. Whereas...