Freakonomics And Abortion

I finally got around to reading Freakonomics. It's a fun, quick read with some interesting theories, best described as a collection of fattened up magazine articles.
The most controversial theory is that Roe Vs. Wade had the unintended benefit of crime reduction in the late 1990s. Steven Levitt's theory goes something like this, for one reason or another these women would have been marginal parents to marginal children many of whom would have ended up being criminals. By aborting them they never lived to be criminals. I for one don't buy it. Primarily because the reduction in crime was so drastic, in some cases reduced by 50%, abortion alone couldn't account for all of it. In fairness I do believe that abortion on demand probably did reduce crime somewhat. This is because a lot of victims of abortion are disproportionately poor and/or black and many criminals tend to be disproportionately poor and/or black as well. Levitt is aware of the moral bankruptcy of this relationship, pointing out that economics are the way people actually behave, morality is the way they should behave. I think we've been down that road before with eugenics at the beginning of the last century and in Germany in the 1930s.
Crime in my opinion was reduced by three things: better policing, new prisons filled with repeat offenders, and the decline in the crack epidemic.
Let's say in a city of 100,000 people there are 300 habitual criminals some of whom sell crack, some of whom use crack. The crack users need to support their habit so on average they commit 3 crimes a day, the dealers in the course of business kill 35 people a year in their drug wars. By arresting and putting them away these 300 people to how much crime is prevented? One whole hell of a lot.