The Supreme Court says judges cannot give convicts extra time in prison in hope it will be used to get them into rehabilitation services.

The high court on Thursday unanimously ruled in favor of Alejandra Tapia, who was trying to reduce her 51 month sentence for alien smuggling, gun possession and bail jumping.

She wanted a three-year sentence, but the judge said that a longer sentence would increase her chances of getting into a 500-hour prison drug rehabilitation program. Tapia was never placed in the program.

Tapia says Congress has disapproved of judges using imprisonment as a method of rehabilitation. The lower courts disagreed.