I was watching Boardwalk Empire, and I idly wondered to myself if the Prohibition era was really all that violent. So I dug up a paper by Leigh Bienen and Brandon Rottinghaus on homicide in Chicago. (We all know that the Atlantic City of the series is fictionalized, so I didn’t bother.)
Answer: a first amateur glance the data says maybe.
Chicago was violent even by modern American standards. The below chart shows homicide rates for the whole city hitting 20 per 100,000 by 1928. That is high. For context, homicide peaked in Chicago in 1991 around 32 per 100,000, declined to around 16 by 2011 and jumped back to 20 last year.
If you look at the red line (for total homicides) it seems to have increased a bit faster after Prohibition starts in 1920 than it had been earlier. But the jump is not that dramatic.
Except it is! Just not for the population as a whole. The blue line shows the homicide rate per 100,000 for white victims only. It continues to increase, but at the same rate as before Prohibition.
The implication is that the victimization rate for non-white Chicagoans must have skyrocketed.
And it did. Right after Prohibition.
In short, violence rose under Prohibition. But it rose more and more-suddenly among a racially marginalized population than in the city as a whole.
What about New York? Homicide rates were generally lower than in Chicago. They were also, unlike Chicago, generally stable in the decades before Prohibition. Homicide rates rise after Prohibition, but later than in Chicago: non-white victimization rates do not jump until rather late in the decade.
I would not ascribe causality; this is all amateur hour.
But there is a sad familiarity to this story, much the same our modern prohibition has destabilized black communities much more than white ones.