Attorney General Janet Reno is considering strategies that could release thousands of inmates from federal prison early and keep others from going there.
Reno has ordered the U.S. Bureau of Prisons to study what impact these "hypothetical strategies" would have on the number of inmates in the nation's 71 federal prisons.
The studies signal a major shift in Justice Department policy, not only to slow the rate of prison growth but to "better serve justice," officials said.
There are 77,906 inmates in the 71 federal prisons nationwide and another 8,493 in federal jails, contract facilities, home confinement or halfway houses.
Justice Department strategies under study include shorter sentences for some non-violent prisoners, especially drug offenders.
The attorney general strongly advocates tough penalties for violent offenders but has frequently said alternative sanctions are appropriate for others if they combine "carrot and stick" rehabilitative measures.
Shortening sentences would, at the least, require changes in mandatory minimum sentencing laws.