The ruling overturns a decision by a federal judge last year dismissing Missouri Attorney General Jay Nixon's lawsuit against two companies behind faxed ads. The judge said the state failed to prove that faxed ads were harmful.
In Friday's ruling, a three-judge panel of the 8th Circuit U.S. Court of Appeals said that "there is substantial governmental interest in protecting the public from the cost shifting and interference caused by unwanted fax advertisements."
Nixon lauded the ruling: "It's certainly a victory for small business owners and other consumers who have been annoyed by getting" junk faxes.
A spokesman for one of the companies, California-based Fax.com, did not return a phone call. The other company named in the suit, American Blast Fax Inc. of Dallas, is no longer in business.
The lawsuit claimed junk faxes tie up consumers' machines, waste their paper and unfairly shift the cost of paper, toner and lost fax line availability to unwilling recipients. The suit cited American Blast Fax's own claim boasting that it sent ads to 125,000 fax machines in St. Louis alone.
The suit also claimed that unsolicited fax ads violate the federal Telephone Consumer Protection Act of 1991, which regulates telemarketing calls and also contains prohibitions against junk faxes.
Besides questioning whether such ads were harmful, last year's lower-court ruling struck down those prohibitions as unconstitutional.
Friday's ruling upholds the 1991 ban, and supports a similar ruling in 1995 by the San Francisco-based 9th U.S. Circuit Court of Appeals.
That ruling called the federal law banning junk faxes "a reasonable means of preventing the shifting of advertising costs to consumers" and not a violation of freedom of expression.
By Jim Salter