What are you talking about? Please explain how legalizing or decriminalizing cocaine, heroin and marijuana (which has never worked by the way) will lead to a lessening of communist insurgency, gang violence or terrorist attacks.
What do you mean by “has never worked” ? More like has never been tried.
It will lead to a reduction in gang violence, by reducing the money available to them. Communist insurgents(FARC) and terrorists (Taliban) use the drug trade as a major source of income. The US is the major destination for those drugs, figure it out.