Does anyone have any data to back this claim up?
(Down voted for pointing out where to get the stats - very funny - must be DOJ folks)
Freakanomics has a long section on it that contradicts Gladwell and I am inclined to believe the Freakanomics since they back it up with stats.
This isn't scientific but It just seems like the 70's had a very chaotic vibe with a lot of external stuff hitting the US. The economy wasn't strong and we were going into a massive transition (factory -> office). Nixon (scandal & economy) and Carter (personified weak) didn't help a whole lot. A lot of in decline thinking causes a lot of unrest and crime.
I would rank most tough crime laws as a cause not a cure.
Probably best to just assume it was an accident. I've done it more than once on mobile.
Does anyone know of any research showing that the decline in murder counts is primarily due to harsher penalties?
(I want to also mention that he debunks quite convincingly the theory that the decrease in crime had anything to do with legalizing abortion.)
[1] see Freakonomics