More Americans went to prison or jail during the Clinton administration than during any past administration.
A criminal justice think tank study has found the high rate of incarceration is the result of get-tough policies that led to more prisons, more police officers and longer sentences.
During President Bill Clinton's eight years in office, 673,000 people were sent to state and federal prisons.
This compares with 343,000 during President George Bush's single term and 448,000 in President Ronald Reagan's two terms, says a study by the Justice Policy Institute.
The incarceration rate at the end of the Clinton administration was 476 per 100,000 citizens, versus 332 per 100,000 at the end of Bush's term and 247 per 100,000 at the end of Reagan's administration, the study says.
Incarceration rates for blacks increased to 3,620 per 100,000 from around 3,000 per 100,000 people during Mr Clinton's two terms.
Two million people are behind bars and 4.5 million are on probation and parole, according to the study, which is based on Justice Department figures and estimates from 1993 to 2000.
The study blames the surge in prisoners on Clinton administration initiatives that provided more money to states for prisons, police officers and crime prevention programs.
Allen Beck, chief of corrections statistics at the Bureau of Justice Statistics, disputes the notion that Clinton administration crime initiatives are the prime reason for the burgeoning prison population.
He says many states had already begun tough crime prevention programs before Mr Clinton came to office and tougher sentencing guidelines for federal drug offenders began in the late 1980s.
Moreover, Mr Beck says, people are staying in jail longer because parole boards are not releasing prisoners.