Like Jim Crow (and slavery), mass incarceration operates as a tightly networked system of laws, policies, customs, and institutions that operate collectively to ensure the subordinate status of a group defined largely by race.

Many people don't realize that financial incentives have been built into the drug war that guarantee that law enforcement will continue to arrest extraordinary numbers of people, particularly in poor communities of color, for minor drug offenses that get ignored on the other side of town.

If the drug war was waged in those communities it would spark such outrage that the war would end overnight. This literal war is waged in segregated, impoverished communities defined largely by race, and the targets are the most vulnerable, least powerful people in our society.

Arguably the most important parallel between mass incarceration and Jim Crow is that both have served to define the meaning and significance of race in America. Indeed, a primary function of any racial caste system is to define the meaning of race in its time. Slavery defined what it meant to be black (a slave), and Jim Crow defined what it meant to be black (a second-class citizen). Today mass incarceration defines the meaning of blackness in America: black people, especially black men, are criminals. That is what it means to be black.

Most Americans violate drug laws in their lifetime, but the enemy in this war has been racially defined. Not by accident, the drug war has been waged almost exclusively in poor communities of color, even though studies have consistently shown - for decades - the people of color are no more likely to use or sell illegal drugs than whites.

The fact that more than half of the young black men in any large American city are currently under the control of the criminal justice system (or saddled with criminal records) is not - as many argue - just a symptom of poverty or poor choices, but rather evidence of a new racial caste system at work.

In the 1990s - the period of the greatest escalation of the drug war - nearly 80 percent of the increase in drug arrests was for marijuana possession, a drug less harmful than alcohol or tobacco and at least, if not more, prevalent in middle class white neighborhoods and college campuses as it is in the 'hood.