Wetherbee said he'd appeal.
Washington's experiment is built around the notion that it can bring marijuana out of the black market and into a regulated system that protects public health and safety better than prohibition did.
But advocates say local bans threaten the state's ability to do that: 28 cities and two counties have banned pot shops, and scores more have issued long-running moratoriums preventing the stores from opening while officials review zoning and other issues.
Fife's lawyers argued that nothing in the state law overruled cities' zoning authority, while Wetherbee's attorneys insisted that if local governments can ban licensed growers, processor and sellers, it would undermine voters' desire to displace illegal pot sales.
Culpepper said Wetherbee did not prove that banning pot shops in such a small city — 5 square miles and fewer than 10,000 people — would thwart the will of the voters; there are shops open in Tacoma, next door.
The analysis might be different for bans in Pierce County or other more populous or larger parts of the state, Culpepper suggested.
The case posed a serious threat to Washington's entire system for regulating marijuana. Fife had asked the judge, if he struck down the city's ban, to consider whether the state law should be invalidated as incompatible with marijuana's prohibition under federal law.
Culpepper said offhandedly that he did not believe I-502 conflicts with federal law, but he did not reach that question in his ruling.
Nevertheless, Culpepper's ruling doesn't end challenge to Fife's ban. The judge said Wetherbee could pursue procedural arguments that the city didn't adopt it properly.
The lawsuit attracted a lot of attention, with the state, the American Civil Liberties Union of Washington, and other counties and towns weighing in.
Washington Attorney General Bob Ferguson took the position that I-502 did not negate local zoning authority to ban the shops, but he insisted that the state's law is not pre-empted by the federal Controlled Substances Act. He called Fife's arguments "a significant threat to the implementation of Initiative 502."
Ferguson said after the ruling that I-502's drafters could have addressed the issue with a single sentence requiring local governments to allow the businesses.
Alison Holcomb, the ACLU of Washington lawyer who wrote the law, said she hopes the Legislature addresses the question. She said the ACLU chapter would support letting cities ban pot businesses, as long as that decision is made by voters, not elected officials.
Rep. Chris Hurst, the Enumclaw Democrat who heads the House committee that oversees the pot industry, said lawmakers might do just that, unless the state Supreme Court overrules Culpepper by January.