shows the homicide rate in the United States from 1910 to 1944.
After Prohibition was passed in 1919, the homicide rate in the U. S. rose; after repeal in 1933, it dropped.
"So what?" you might ask.
Well, I can't believe I'm citing a piece by the American Enterprise Institute, but I agree with its argument, "Chicago’s gun violence can be traced to drug prohibition":
What’s fueling the gun violence and homicides in Chicago? Hint: It’s
the same factor that has led to the death of more than 60,000 victims in
Mexico. And that factor is America’s senseless and failed War on Drugs.
The author references another piece in Bloomberg, "Heroin Pushed on Chicago by Cartel Fueling Gang Murders":
“Most of Chicago’s violent crime comes from gangs trying to maintain control of drug-selling territories,” says Jack Riley, head of the U.S. Drug Enforcement Administration for a five-state region that includes Illinois.
The link between drugs and crime, including violent crime, would be hard to overstate in Chicago.
As someone whose great-uncle* was shot and killed by Al Capone's gang in the Roaring Twenties, I agree: legalize drugs tomorrow and watch the gun violence fade away.
* From "Still standing: Al Capone's roots in Chicago, part 1, Cicero" (my emphasis):
By 1926, Capone was well known, respected, and feared. It was public
knowledge that he was running the Chicago Outfit as well as the town of
Cicero, so it was inconceivable that a group of small time thugs wanting
a piece of the illegal liquor action would muscle in on his territory -
but they did. On the night of April 27, 1926, the Myles brothers and
their friend "Klondike" Bill O'Donnell met up with a few known gangsters
and an acquaintance. The group decided to go out for a good time at the
Pony Inn at 5613 West Roosevelt Rd, Cicero, just blocks away from 1600
Austin. As they stood in front of the inn, the orange flash of a machine
gun lit the night, aiming for the Myles brothers and O’Donnell. After
the car passed, the thugs’ acquaintance turned out to be assistant
state's attorney William "Billy" McSwiggin; the hit had gone bad, and he
bled to death on the sidewalk, along with gangsters James J. Doherty
and Thomas Duffy. It's widely believed that Capone did not just order
the hit, but manned the gun used in the killings himself.