Academic asks why America has so many people in prison; can't possibly be due to crime rate, right?

A totally leftist website--a waste of electrons--has a piece by an academic titled "Why are so many "Americans in prison--a provocative new theory."  And while I hate to give loony left-wing sites links, you really need to read it to see how utterly bereft of reason those folks are.

The academic notes that the number of people in prison is up about five-fold since 1960, but the crime rate is only four times higher over the same period.  This of course must be a plot, and surely a scandal:  How can the number of prisoners have increased more than the crime rate??

Of course a big chunk of the increase in the prison population is simply due to the fact that the U.S. population is about 70 percent higher than 1960--but obviously that leaves a lot of the increase unexplained.

The academic acknowledges that state legislatures have passed mandatory sentences for some crimes, but then notes that the length of sentences actually served hasn't changed.  He notes that there's more drug crime now than in 1960, but the percentage of prisoners doing time for drug crimes is only about 20 percent--not enough to account for the gap.

Eventually he claims the main cause is that local DA's are charging a higher percentage of accused than in the past.  He claims this is due to a higher desire by DA's to be re-elected, or a desire to run for higher office.

I suggest DA's are taking a lot of cases to trial that they couldn't in 1960 because of the growing availability of DNA evidence.  I suggest a second factor is that public disgust with skyrocketing crime has increased pressure to put criminals in prison.  Together I think these two can easily account for the five-to-four ratio of inmates to crimes.

The real sticking point is why crime is up four-fold since 1960 when population is only up 70 percent.  One commenter offered this:

I have a friend who has recently started his career in criminal law, and he has a lot to say about the people he defends in court.  He frequently says how shockingly unperceptive and clueless his clients are, and how surprised they are--again and again and again--that  they get caught.

He hates to use the word "dumb" but admits that a lot of them really are--there is just no sugar-coating it.

Other commenters jumped on this, claiming the average IQ of the whole population couldn't have changed enough to matter.  But I think they're missing a huge change in the urban demographic:

Fifty years ago, before the catastrophic destruction of a huge percentage of low-functioning families, dumb people got enough parental input--including a lot of moral teaching imparted by churches--to avoid committing *serious* crime.  But now that's all gone, replaced by the ethos of "I want it, so I'm gonna take it."

Someone else noted that the figures for drug crime don't include burglaries and robberies committed to get money to buy drugs.  So we may be seriously underestimating the social cost of drugs.

Hmm....