The Racial Disparity The sheer volume of law enforcement resources devoted to marijuana is bad enough. What makes the situation far worse is racial disparity. Whites and blacks use marijuana at roughly the same rates; on average, however, blacks are 3.7 times more likely than whites to be arrested for possession, according to a comprehensive 2013 report by the A.C.L.U.

In Iowa, blacks are 8.3 times more likely to be arrested, and in the worst-offending counties in the country, they are up to 30 times more likely to be arrested. The war on drugs aims its firepower overwhelmingly at African-Americans on the street, while white users smoke safely behind closed doors.

Only about 6 percent of marijuana cases lead to a felony conviction; the rest are often treated as misdemeanors resulting in fines or probation, if the charges aren’t dismissed completely. Even so, every arrest ends up on a person’s record, whether or not it leads to prosecution and conviction. Particularly in poorer minority neighborhoods, where young men are more likely to be outside and repeatedly targeted by law enforcement, these arrests accumulate. Before long a person can have an extensive “criminal history” that consists only of marijuana misdemeanors and dismissed cases. That criminal history can then influence the severity of punishment for a future offense, however insignificant.

While the number of people behind bars solely for possessing or selling marijuana seems relatively small — 20,000 to 30,000 by the most recent estimates, or roughly 1 percent of America’s 2.4 million inmates — that means nothing to people, like Jeff Mizanskey, who are serving breathtakingly long terms because their records contained minor previous offenses. Nor does it mean anything to the vast majority of these inmates who have no history of violence (about nine in 10, according to a 2006 study). And as with arrests, the racial disparity is vast: Blacks are more than 10 times as likely as whites to go to prison for drug offenses. For those on probation or parole for any offense, a failed drug test on its own can lead to prison time — which means, again, that people can be put behind bars for smoking marijuana.

Even if a person never goes to prison, the conviction itself is the tip of the iceberg. In a majority of states, marijuana convictions — including those resulting from guilty pleas — can have lifelong consequences for employment, education, immigration status and family life.

A misdemeanor conviction can lead to, among many other things, the revocation of a professional license; the suspension of a driver’s license; the inability to get insurance, a mortgage or other bank loans; the denial of access to public housing; and the loss of student financial aid.