But Mac Donald cites studies of charging and sentencing that demonstrate that the reason more blacks are disproportionately in prison, and for longer terms, is not racism but racial differences in patterns of criminal offenses: "In 2005 the black homicide rate was over seven times higher than that of whites and Hispanics combined. ... From 1976 to 2005, blacks committed over 52 percent of all murders." Do police excessively arrest blacks? "The race of criminals reported by crime victims matches arrest data."
As for the charge that the incarceration rate of blacks is substantially explained by more severe federal sentences for crack as opposed to powder-cocaine defendants (only 13 states distinguish between the two substances, and these states have small sentence differentials), Mac Donald says:
"It's going to take a lot more than 5,000 or so (federal) crack defendants a year to account for the 562,000 black prisoners in state and federal facilities at the end of 2006 -- or the 858,000 black prisoners in custody overall, if one includes the population of county and city jails."
James Q. Wilson, America's premier social scientist, notes that "the typical criminal commits from 12 to 16 crimes a year (not counting drug offenses)" and Wilson says that 10 years of scholarly studies "have shown that states that sent a higher fraction of convicts to prison had lower rates of crime, even after controlling for all of the other ways -- poverty, urbanization, and the proportion of young men in the population -- that the states differed. A high risk of punishment reduces crime. Deterrence works." It works especially on behalf of blacks, who are disproportionately the victims of crimes by black men.
A recent report by the Pew Center on the States asserts that America incarcerates too many people, and in the process diverts money from higher education. Wilson notes that the report does not examine whether the slower growth of public spending on higher education than on prisons may be explained by the surge in private support for public universities. And, Wilson dryly adds, the report does not explore "whether society gets as much from universities as it does from prisons." A good question, but not one apt to be studied in academia.