The guidelines set rules for judges to calculate punishment and attempt to reduce wide disparities in sentences for the same crime.

But critics of the guidelines say they often impose overly harsh sentences and take away a judge's discretion to look at the facts of the case and fit an appropriate punishment for each individual.

The ruling involved Victor Rita, who received 33 months in prison for making false statements during an investigation of illegal trafficking in machine gun kits. His sentence was at the bottom of the guideline range of 33 to 41 months.

Rita had sought a sentence lower than 33 months, based on his physical condition -- he has diabetes and other illnesses -- his likely vulnerability in prison and his military service in Vietnam and in Operation Desert Storm.

The Supreme Court upheld a U.S. appeals court's ruling that found Rita's sentence to be reasonable.

Justice Stephen Breyer said in the majority opinion that the judge in the case properly analyzed the relevant factors and gave legally sufficient reasons for the sentence.

The ruling followed up on the Supreme Court's landmark decision in 2005 that federal judges no longer were bound by the sentencing guidelines that had been in effect for nearly 20 years, but must consult them and take them into account.

Justice David Souter dissented in Thursday's decision and said he would reject the presumption of reasonableness adopted in the case. He also urged Congress to revisit the issue of guidelines.