A national "Do Not Call" registry scheduled to begin Oct. 1 could be sidelined by a federal judge's ruling.
U.S. District Judge Lee R. West ruled the Federal Trade Commission overstepped its authority against telemarketers.
The decision came in a lawsuit filed by telemarketers. They challenged the list of more than 50 million telephone numbers submitted by people who don't want phone solicitations.
A similar lawsuit is pending in U.S. District Court in Denver. The Colorado Legislature approved a local "No Call" registry last year.
The immediate impact of the ruling is unclear. West did not direct the FTC to take any action.
West says Congress gave the Federal Communications Commission, not the FTC, the authority to regulate phone solicitations.
The decision won't affect Colorado's No Call List.