Important correction - the significant political power in the US comes from the prison guards union, not a "private prisons lobby". The prison guards union is

Important correction - the significant political power in the US comes from the prison guards union, not a "private prisons lobby". The prison guards union is an incredibly powerful lobbying force, which has successfully increased prison sentences for many crimes, blocked efforts to decriminalize marijuana, made more mandatory sentences, etc. Whether those guards work in the 92% of prisons which are government run or the 8% which are privately run makes no difference.