OAKLAND, Calif. – Protesters, many of them medical marijuana users, massed in downtown Oakland April 2 to protest the raiding by federal agents of Oaksterdam University, which trains workers for the medical marijuana industry. Agents also raided other sites identified with Oaksterdam founder Richard Lee, California’s best-known backer of legalizing and regulating marijuana.

The agents from the U.S. Internal Revenue Service, Drug Enforcement Agency and U.S. Marshals Service removed files, a safe, black trash bags and marijuana plants from the various locations, but wouldn’t say why they conducted the raids.

Protesters shouted “Shame!” and “DEA go away” and some lay down in the street or moved their wheelchairs in front of federal vehicles. Two demonstrators were reportedly arrested.

In 1996, California voters passed Prop. 215 legalizing medical cannabis use with a California-licensed physician’s prescription. Fifteen other states and Washington D.C. also permit use of marijuana for medical purposes, though it continues to be illegal under federal law.

In 2003 Oakland became the nation’s first city to regulate dispensaries. In succeeding years, city ballot measures made possessing small amounts of pot the lowest priority for police, and provided for regulating and taxing medical cannabis businesses.

With a July 2010 City Council vote, the city became the first U.S. city to authorize industrial-scale production of medical marijuana. . Four dispensaries now operate, bringing the city $1.7 million in taxes, and permits are in process for another four.

In other parts of California the picture is mixed, with struggles taking place around local efforts to license dispensaries.

Early in the Obama administration, the U.S. Justice Department had said it wouldn’t focus on medical cannabis dispensaries that followed state law. But last October, alleging many supposedly non-profit clinics are raking in money by supplying people with no medical need, the Justice Department began moving against dispensaries even where states allow them.

Oakland City Councilmember Rebecca Kaplan, who joined demonstrators as they protested the raids, told radio station KPFA the city was not involved in or notified of the raids. She said “extra law enforcement resources” should be used instead against illegal gun dealing, which she called a “deadly crime” that is “causing death throughout Oakland.”

The reference was particularly poignant in view of the tragedy that had just taken place, when a gunman identified as an angry former student allegedly opened fire at a religious school in another part of the city, killing seven people and injuring three. Some 27 homicides had already occurred in Oakland this year.

State and local legislators in states where medical marijuana is legal have been fighting back against the federal campaign for some time. Right after the Oakland raids, seven state legislators from five states where medical pot is legal – five Democrats and two Republicans – sent an open letter urging President Obama to follow his campaign promise and leave its regulation to the states.

Two Californians, Assembly members Tom Ammiano, D-San Francisco, and Chris Norby, R-Fullerton, are among the signers.

The letter said the states have “embraced an approach that is based on science, reason and compassion,” and called on the federal government “not to interfere with our ability to control and regulate how medical marijuana is grown and distributed.”

Photo: U.S. marshals at the entrance of Oaksterdam University in Oakland. Noah Berger/AP