Today federal agents, assisted by local police, staged the biggest crackdown on marijuana dispensaries in Colorado since the state legalized cannabis for medical use in 2000. The Denver Post reports that the raids hit more than a dozen dispensaries in the Denver area, plus businesses in Boulder and elsewhere.

Jeff Dorschner, a spokesman for John Walsh, the U.S. attorney for Colorado, said the operation "comports with the Department's recent guidance regarding marijuana enforcement matters." The August 29 memo to which Dorschner refers indicated that the feds would not interfere with marijuana businesses that comply with state law unless their activities implicated one or more of these eight "enforcement priorities": 1) "preventing the distribution of marijuana to minors," 2) "preventing the diversion of marijuana from states where it is legal under state law in some form to other states," 3) "preventing drugged driving and the exacerbation of other adverse public health consequences associated with marijuana use," 4) "preventing the growing of marijuana on public lands," 5) "preventing marijuana possession or use on federal property," 6) "preventing revenue from the sale of marijuana from going to criminal enterprises," 7) "preventing violence and the use of firearms in the cultivation and distribution of marijuana," and 8) "preventing state-authorized marijuana activity from being used as a cover or pretext for the trafficking of other illegal drugs."

Which of those concerns triggered today's raids? Walsh's office won't say, at least not yet. "Although we cannot at this time discuss the substance of this pending investigation," Dorschner said in a written statement, "there are strong indications that more than one of the eight federal prosecution priorities identified in the Department of Justice's August guidance memo are potentially implicated."

The raids come just six weeks before Colorado's state-licensed pot shops are scheduled to start selling marijuana for recreational use. But industry leaders seem to be viewing their competitors' legal troubles with equanimity. "Really, I see enforcement actions happening as a sign our industry is maturing and this program is working," Mike Elliott, president of the Medical Marijuana Industry Group (MMIG), told the Post, although he did add that "it's important to remember people are innocent until proven guilty." MMIG board member Andy Williams, who runs Denver's Medicine Man dispensary, appeared pleased as well. "I want the bad actors gone, quite honestly," he said.

Mason Tvert, who co-managed Colorado's legalization campaign and now works for the Marijuana Policy Project, was a bit more wary. "The Justice Department said it would respect states' rights to regulate marijuana, and that it would not go after businesses as long as they are complying with state laws," he said. "We hope they are sticking to their word and not interfering with any state-regulated, law-abiding businesses." Rob Corry, a Denver attorney and marijuana activist, told the Post: "The DOJ needs to explain in a logical fashion why they are picking and choosing, going after only some of these entities when every one of them selling marijuana is running afoul of the federal law."

These raids are an unusually aggressive move by Walsh, who until now had mostly contented himself with shutting down dispensaries he deemed too close to schools by sending them threatening letters. But the Justice Department's new policy regarding state-legal marijuana businesses leaves a lot of leeway for prosecutorial discretion. If I were a dispensary owner planning to get into the newly legal recreational market, I would pay careful attention to Walsh's explanation, assuming he ever offers one, of exactly how businesses such as VIP Cannabis crossed the Justice Department's faintly marked red lines.