Colorado's Amendment 64, the ballot initiative through which the state opted out of marijuana prohibition, allows local governments to opt out of legalization. To a point. The initiative, which is now part of the state constitution, lets municipalities and counties ban pot stores within their borders, but it bars them from punishing residents for possession or home cultivation. Greenwood Village, an upscale, marijuana-unfriendly suburb of Denver, seems to have crossed that line in the guise of regulation.

Under Amendment 64, cities can ban marijuana businesses by ordinance or by referendum, with a requirement that the referendum occur in an even-numbered year (meaning November 2014 at the earliest). Furthermore, the marijuana law enacted by the state legislature in May makes local approval a condition of state licensing. As of September, more than 60 counties and municipalities had imposed bans or moratoriums on pot shops.

Greenwood Village, a town of 14,000 with a median family income of about $150,000, went further. The city council pre-emptively banned pot shops immediately after the passage of Amendment 64, which most of the town's voters opposed. Then, in January, it enacted an ordinance that purports to ban possession of marijuana or "marijuana accessories" on city property, including streets and sidewalks.

The upshot is that residents of the town may grow up to six plants in their homes, as allowed by Amendment 64, but may not take any of that marijuana anywhere else. They may not share their marijuana with friends, which is also permitted by the amendment, unless it's consumed in the same place where it's grown. Finally, the town's residents may not buy marijuana at a licensed store in another city and bring it home, since that would require possessing it on the streets of Greenwood Village. People passing through town after legally buying marijuana elsewhere apparently would be violating the ordinance as well.

Even the right to grow pot at home would be mainly theoretical, since the "accessories" banned from city streets and sidewalks include "any equipment, products, or materials of any kind" used to produce marijuana. That provision contradicts another ordinance approved by the city council that requires home growers to purchase and install ventilation systems.

The pot ban's sponsor, Leslie Schluter, argues that the city has the authority to impose these restrictions because it owns the property where they apply. "This is appropriate regulation to limit marijuana," she says. "Greenwood Village, as the property owner, does not wish to have marijuana on city streets or city sidewalks." City officials note that Amendment 64 expressly allows "a person, employer, school, hospital, detention facility, corporation or any other entity" to prohibit marijuana possession on its property.

Yet interpreting that clause to cover public streets and sidewalks, such that someone can be punished merely for driving through Greenwood Village with a sealed package of legally purchased pot in his glove compartment, clearly runs afoul of Amendment 64's command that possessing or transporting up to an ounce of marijuana "shall not be an offense under Colorado law or the law of any locality within Colorado." Denver attorney Rob Corry, who specializes in marijuana cases, says he'd be happy to represent anyone cited under Greenwood Village's ordinance. "That will fall if challenged," he says.

Although Corry doubts that a resident of Greenwood Village would be willing to offend his neighbors by challenging the ordinance, a motorist passing through might be less reluctant. "When that ticket is issued," he says, "if that case comes across my desk, then there's an easy constitutional challenge to the ordinance." Even The Denver Post, which editorialized against Amendment 64, condemned Greenwood Village's ban on pot possession in February, asking: "Are city officials under the impression that a constitutional amendment can be edited by local communities even after it has passed? If not, how do they expect the amendment's reference to 'transporting' marijuana to be honored if they've effectively outlawed that activity within their locale?"

Greenwood Village's attempt to override Amendment 64 reflects a deeper and more widespread anxiety among pot prohibitionists. Greenwood Village Police Chief John Jackson no doubt speaks for many law enforcement officials when he wonders how his officers can be expected to distinguish between an illegal pot stash and the perfectly legal produce of home cultivation. At one of the working group meetings leading up to the report issued by the Amendment 64 Implementation Task Force in March, Jackson recoiled at the "appalling," "horrendous," and "ridiculous" prospect of letting someone keep several ounces of homegrown marijuana, even though that is what Amendment 64 clearly requires, provided the pot comes from six or fewer plants. "I suppose he has a right to be appalled," says Corry, "but the voters decided that his outrage should no longer have criminal consequences."