I can't speak for anywhere else, but I know that in Chicago, most gun violence is about settling scores, not about drug trafficking. Ending the war on drugs would keep a lot of non-violent offenders out of jail, but when teenagers who have never been to jail in the first place are shooting each other, you have to take a different approach.
Just last night -
"A 17-year-old boy was shot in the 2100 block of North Mulligan Avenue about 9:50 p.m. He was taken to Advocate Illinois Masonic Medical Center in good condition with a wound to his thigh, Police News Affairs Officer Ron Gaines said.
Another 17-year-old boy was shot in the back near 70th Street and Perry Avenue about 8 p.m. He was taken to Stroger Hospital, where his condition was stabilized."