WASHINGTON (CNN) -- The Justice Department has provided federal prosecutors "clarification and guidance" urging them to go after drug traffickers, but not patients and caregivers, in the 14 states that have medical marijuana laws.
Signs beckon patients into a medical marijuana clinic in Los Angeles, California.
A memo sent to U.S. attorneys said that in carrying out Justice pronouncements made earlier this year indicating a policy shift to end prosecutions against users, authorities should continue to pursue drug traffickers.
"It will not be a priority to use federal resources to prosecute patients with serious illnesses or their caregivers who are complying with state laws on medical marijuana," said Attorney General Eric Holder. "But we will not tolerate drug traffickers who hide behind claims of compliance with state law to mask activities that are clearly illegal," Holder added.
The memo from Deputy Attorney General David Ogden was sent to U.S. attorneys in Alaska, California, Colorado, Hawaii, Maine, Michigan, Montana, Nevada, New Mexico, Maryland, Oregon, Rhode Island, Vermont and Washington.
The issue is particularly significant in California, where there has been uncertainty about the government's approach to raiding marijuana dispensaries, which are increasing and thriving.
At the White House, spokesman Robert Gibbs said, "I'm not going to get into what states should do. The memo that was sent out today to U.S. attorneys simply adds guidelines to a decision that Attorney General Holder talked about in mid-March and has been administration policy since the beginning of this administration in January."
That policy marks a shift from the Bush administration's position, backed by the Supreme Court, that federal agents have a right to pursue marijuana dispensaries and customers any time federal drug law alone has been violated.
The National Organization for the Reform of Marijuana Laws, which advocates legalization of marijuana, declared the government's memo Monday a "major departure in the so-called war on drugs" and "a major victory for citizens who support cannabis law reform."
Drug Enforcement Administration officials disputed that assertion.
"We remain committed to pursuing large-scale criminal drug trafficking organizations," said one DEA official. "If you look at who we've gone after, you'll find they're clearly breaking California law. The threshold is state and local law."
The Justice Department guidance said it would not be a wise use of federal resources to go after "individuals with cancer or other serious illnesses who use marijuana as part of a recommended treatment regimen consistent with applicable state law."
But Ogden's memo warns that federal authorities will continue to pursue signs of illegal trafficking in drugs, including marijuana. The memo says such characteristics would include "unlawful possession or use of firearms, violence, sales to minors, money laundering, illegal possession or sale of other controlled substances, or ties to other criminal enterprises."