In the last two decades there has been an unprecedented increase in imprisonment in the United States. This expansion of imprisonment did not happen in other Western Democracies and, more importantly, it happened unevenly among the fifty states. Why was there such variation among the fifty states? Was it associated with increased rates of reported crime in each state? Are there socio-economic variables that are salient for prison growth?

The literature on the subject of variations in imprisonment patterns is limited. Three theories have been offered to explain the growth of imprisonment. The first could be called the" Durkheim-Blumstein" tradition, the second is the" Marxist-Rusche and Kircheimer" tradition and a third is the" racial-bias" theory. The first argues that a society''s crime rate determines it''s imprisonment rate; the second argues that economic factors are salient for imprisonment rates. The" racial-bias" theory suggests that the war-on-crime is really a war on African-Americans.