According to a report from the Detention Watch Network, private prisons spent $20,432,000 lobbying the federal government over the decade 1999-2009. That's an astounding amount of money, especially given the fact that there's no realy counter-lobby to the industry. No group spends any significant amount of money lobbying against private prisons. And that's just the federal government; that figure doesn't include state lobbying money, or money spent on campaign contributions or donations to political action committees (PACs).
This has resulted in our government sending nearly half of its immigrant detainees into private custody, and nearly 1 out of every 5 federal prisoners are in a private prison.