An opponent of legalization says it would exacerbate inequality in the United States. But he fails to account for the impact of jail time on inequality under currents laws.

In recent years, David Frum has consistently expressed concern for growing inequality in the United States. He is probably right to worry, but I must protest his most recent argument. "It's baffling to me that people who profess anxiety about the trend to social inequality will so often endorse drug legalization," he wrote. "A world of legal drugs will be a world in which the fates of the top one third of Americans and the lower two thirds will diverge even more than they already do. A world of weaker families, absent parents, and shriveling job opportunities is a world in which more Americans will seek a cheap and easy escape from their depressing reality. Legalized marijuana, like legal tobacco, will become a diversion for those who feel they have the least to lose."

Let's presume for the sake of argument that legalized marijuana will increase use more among the lower two-thirds of American households, and that some of these users wind up abusing the drug.

Quantify the harm in your unit of choice.

Now let's ponder whether marijuana prohibition creates even more dramatic harm, and whether the burden falls most heavily on relatively poor people. If you're baffled that someone would want to reduce inequality and legalize marijuana, this little exercise is guaranteed to edify.

• Even controlling for different levels of use, poor people are arrested more frequently than their upper middle class equivalents, are more likely to be found guilty, and are sentenced to harsher penalties.

• The violence associated with a black market in marijuana causes the vast majority of its harm in poorer neighborhoods and poorer countries. 

• The economic incentive to become a drug dealer acts far more powerfully on poor kids than richer kids. 

• Incarceration associated with marijuana does far more damage to poor families than to rich families, and affects the supply of marriageable men far more in poorer than richer neighborhoods.
  

It is incontestable that the War on Drug's burdens fall most heavily on the poor, and it makes no sense to discuss how marijuana legalization would affect inequality in America without grappling with the specific ways that marijuana prohibition exacerbates inequality, especially since its costs -- years spent in prison, police intrusion into private homes, bullets flying in one's neighborhood, etc. -- are often so much more life-altering than all but the most unusual recreational use.