Elaine Thompson / AP file Different strains of marijuana were displayed in February 2013 during the opening of the Seattle location of the Northwest Cannabis Market.

Washington state cities and counties can weed out pot stores even though voters approved them in a referendum, the state attorney general said Thursday.

Attorney General Bob Ferguson wrote in a formal legal opinion (.pdf) that the 2012 ballot initiative legalizing possession of up to an ounce of pot for recreational use — known as I-502 — neglected to specify that statewide marijuana regulations would trump local laws.

Dozens of Washington municipalities, including major cities like Walla Walla and Yakima, have already adopted measures to snuff out marijuana growing operations, processing facilities and retail shops.

Local officials can clamp down on pot purveyors in any of several ways: by outright banning them, by zoning them out of existence or by enforcing regulations that require local businesses to obey federal law — which still considers marijuana an illegal drug.

The State Liquor Control Board, which was put in charge of marijuana regulations, sought the AG's opinion to clear up who had the final say — the state or local authorities. It said the state law was intended to ease access to regulated pot statewide so users wouldn't be driven to the black market.

But Ferguson said Thursday that the state constitution gives great weight to local laws, and because the initiative's sponsors failed to explicitly declare that it would supersede local regulations, "normal powers of local governments to regulate within their jurisdictions" remained in place.

The chief author of I-502, Alison Holcomb, director of criminal justice programs for the American Civil Liberties Union of Washington, bluntly told NBC News, "I think the attorney general got it wrong."

Holcomb said it would have been redundant to load up the initiative with extra language saying state law was the law statewide, because it already had the authority to provide "adequate access to licensed sources" of marijuana.

"If the counties are allowed to ban the stores, that directly conflicts with the statute's requirement that there be adequate access," she said.

The attorney general's opinion isn't binding, but it does put the weight of the state's senior legal authority behind marijuana opponents' contention that the state liquor board should take local regulations into account when it issues marijuana business licenses — something it has until now said that it wouldn't do.

That puts entrepreneurs who already applied for state marijuana business licenses in a pickle, Holcomb said, because they "relied in good faith on the Liquor Control Board."

In the attorney general's words, however, the answer is simple: "If the Legislature wants to change that, it can amend the law," he said in a statement accompanying his opinion.

At least 10 legislators are trying to do just that.

The House members introduced a bill Wednesday that would require cities and counties treat marijuana business, including retail stores, just like any other business that wants to set up shop.

Specifically, the bill would ban zoning regulations that restrict pot businesses. Localities that disobey would be frozen out of state liquor license payments — a major chunk of many counties' budgets.

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