SEATTLE — A federal judge has ruled that the city can no longer enforce its 17-year moratorium on new strip clubs, saying it is an unconstitutional restraint on free speech.

But if the City Council votes next week to adopt a new rule banning lap dances, a few new strip clubs may open, anyway.

In his 13-page ruling issued Sept. 12, U.S. District Judge James L. Robart said the city’s rationale for repeatedly extending the ban lacked merit. The city had argued that it was not a censorship issue, but that city officials were waiting for the state and county to adopt cabaret regulations, and that the city’s Department of Planning and Development was overworked.

“The city’s intent and motive for violating the constitution are of no consequence,” Robart wrote in ASF Inc. v. Seattle.

Marianne Bichsel, a spokeswoman for Mayor Greg Nickels, said the ruling was not unexpected. Nickels has proposed a “4-foot” rule for the city’s strip clubs, which would mean exotic dancers must remain 4 feet from their clientele, and the city is working to develop new zoning regulations for strip clubs.

Without the zoning regulations, “You could zone strip clubs in neighborhoods throughout the city,” she said. “That’s what we’re trying to prevent.”

Surrounding communities have the 4-foot rule, she said. If Seattle is the only community that doesn’t, there might be a rush of strip clubs seeking to open in the city.

The City Council is expected to vote next week on the proposal, which has drawn protests from the city’s club owners and exotic dancers, who fear it will severely cut into their business.

The city first imposed a temporary moratorium on new adult cabarets in 1988, after the number of strip clubs in Seattle jumped from two to seven over two years. The moratorium has been repeatedly extended since then.

Robert Davis, president of ASF Inc., sued over the ban after he was denied a license to open a strip club in spring 2004. Davis’ lawyer did not immediately return a call seeking comment.