ORLANDO, Fla. -- A federal judge ordered the release of two sex offenders accused of failing to comply with the Adam Walsh Act, calling the law's registration provisions unconstitutional.

U.S. District Judge Gregory Presnell dropped charges of failing to register as a sex offender against Robert D. Powers, 43, and Tommy William Buckius, 60, both of Orlando.

The men had been arrested on federal charges that they failed to notify authorities when they moved to Florida from other states.

But Presnell said Friday that the requirement to register under a 2006 federal law was largely a local issue, not a federal crime. The men's lawyers argued that Congress lacked the authority to force state sex offenders solely convicted of local offenses to register, and that both men were convicted of crimes before the new law was passed and should not be subjected to them.

Powers has been released from a Seminole County jail. He was convicted in 1995 of a sex assault in South Carolina and was freed two years later. He visited Orlando repeatedly in the late 1990s and lived with his mother in 2007.

Buckius remained in custody and was to have a hearing on an out-of-state charge. He pleaded guilty to the attempted rape of a 13-year-old girl in Ohio in 1986 and was released from prison in 2000. He apparently moved to Florida in late 2006 or 2007.

The Adam Walsh Act was named after a 6-year-old South Florida boy who was abducted and killed in 1981. His father, John Walsh, has since become a crusader for stricter penalties for sex offenders and the host of the television show "America's Most Wanted."

Violating the sex offender registration requirement can result in a 10 year prison sentence, but judges have grappled with how to handle inmates who were convicted prior to the bill's enactment.

Federal prosecutors argued Powers and Buckius should be punished because of an Attorney General's rule that applied to sex offenders before the law took effect in 2007.

But Presnell's ruling stated the registration provisions went too far.

"The Adam Walsh Act was enacted with a commendable goal -- to protect the public from sex offenders," Presnell wrote. "However, a worthy cause is not enough to transform a state concern (sex-offender registration) into a federal crime."