It certainly was a tumultuous period, but what reliable evidence is there of cocaine being a major causal factor? The USA was plagued by lots of labor-related v

It certainly was a tumultuous period, but what reliable evidence is there of cocaine being a major causal factor? The USA was plagued by lots of labor-related violence, race rioting and organized crime (peaking during Prohibition, of course), but was cocaine ever anything more than a scapegoat?