Illinois' Attorney General Lisa Madigan has attacked the revival of the 'debtors' prisons' - something most people associate with Dickens novels.
The Wall Street Journal has flagged up an increasing number of debt-related incarceration, with the debts ranging from bills for health care services to credit card and car loans.
In Missouri, the state constitution outlaws imprisoning someone for unpaid debts.
Tutu argued that different standards appeared to apply for prosecuting African leaders than western counterparts, and added that the death toll during and after the Iraq conflict was sufficient for Blair and Bush to face trial.