The two most important graphs for understanding U.S. law enforcement:
Total state and federal prisoners: http://www.sentencingproject.org/images/photo/State%20and%20....
Total violent crime: http://4.bp.blogspot.com/-zJiRb6FKYgM/Tqil-T4fLpI/AAAAAAAAAF....
Violent crime increases almost 5x from the mid 1960's to the early 1990's. The number of state and federal prisoners consequently increases 5x during that period. That's not the result of "for-profit justice." That's the result of people supporting aggressive enforcement and incarceration in response to skyrocketing violent crime.
The real problem is: what happens after 1995? Violent crime drops by over a third. Yet, prison population continues to grow until it plateaus in the mid-2000's. That's where jobs and budgets come in. They make it difficult to dismantle the whole apparatus, and indeed, to really convey to the public that crime has in fact dramatically decreased.
That said, I think the solution to this is time. U.S. prison population has been trending down for the last several years. The baby boomer generation's attitudes towards crime were forged during the 1970's and 1980's as crime skyrocketed, but that attitude will start to die out as the boomers do.