JOHN TIERNEY: Prison and the Poverty Trap. “The number of Americans in state and federal prisons has quintupled since 1980, and a major reason is that prisoners serve longer terms than before. They remain inmates into middle age and old age. . . . When researchers try to explain why AIDS is much more prevalent among blacks than whites, they point to the consequences of incarceration, which disrupts steady relationships and can lead to high-risk sexual behavior. When sociologists look for causes of child poverty and juvenile delinquency, they link these problems to the incarceration of parents and the resulting economic and emotional strains on families.”