You can’t predetermine a percent of the population that should be in prison. Having a quota of people the government imprisons is frightening beyond words. Ideally, the answer is 0%. Perhaps we have a guideline from countries with democracies we want to call ourselves being in the same caliber:
I look at this chart, and I think, I’d like to at least have a rate similar to the United Kingdom, the place from which our country was supposed to symbolize freedom.
You miss the point of problems with a for-profit prison system entirely. When you put in place a perverse incentive — similar to the problem with private health insurance — that creates an industry that wants to grow. If your for-profit prison industry wants to grow, it lobbies for the War on Drugs, for tougher sentencing, harsh punishments in general, etc. It creates an industry that wants to fill cells. The more heads in the beds, the more the profit. Do you get it now? When government is in charge of incarceration, it actually has the incentive to reduce harsh sentencing, because it doesn’t have the funding to crowd cells.