Stupid people have way more kids than smart people. A normal middle class woman with a good family might have 1 child. A ghetto class woman will have 4 kids and the father of those kids is in jail. 1/2 of parents in this example would be ghetto class, but 4/5 kids would say their dad is in jail. From that sample you would say it's "normal" for daddy to be in jail.
		
		
	 
There's an argument out there by one African-American economist that pegs the breakdown of the black family to LBJ's Great Society welfare state. Made it easy for low income parents to get subsidies. Thus they tended to have more since it lessened the consequences. A lot of these boys grow up in crime ridden neighbourhoods with no strong, positive male role models. They never learn how to be a man, how to be responsible, or how to treat women. They get in with the gangs to fill in that gap and the cycle continues. 
I think the problem started long before the War on Drugs. Goes beyond some bum selling a bit of weed. The war itself was a response to the crack epidemic of the 1980s. I don't see any government legalizing hard drugs like this anytime soon. So what do you do?