The addicted warriors who worship the god of illegal drugs cause drug enforcement to come in by breaking known laws.Unfortunately, it is you who has it backwards. Tell me, did the rise of the mafia gangs (Al Capone, etc.) occur before, or after the enactment of the XVIII Amendment? And did the violence end and the gangs find more peaceful pursuits before or after the enactment of the XXI Amendment? Are you aware of the chronology of the rise of the Asian and South American gangs in the latter part of the 20th Century?
Crime has always come before enforcement. It's even Biblical. Remember Adam and Eve?
As far as gangs coming here form all over in the 20th century, well that little invention called the airplane did help advance bringing folks of all kinds back and forth across the world.
Thanks for your post.