Is this really that hard to figure out?

This article [at least this topic] gets printed in the NYTs every few months:

"The continuing increase in the prison population, despite a drop or leveling off in the crime rate in the past few years, is a result of laws passed n the 1990's that led to more prison sentences and longer terms, said Allen J. Beck, chief of corrections statistics for the department's Bureau of Justice Statistics and an author of the report. "

I know I voted as a "Red-Stater" - so I must be ignorant - but is it so unthinkable that: If you take -and keep - criminals off the street, crime will drop?