Worried about recent violence at homes with backyard pot farms, Fresno County supervisors Tuesday approved an emergency ban on outdoor medical-marijuana cultivation in unincorporated areas.

Despite campaign promises to the contrary, the Department of Justice under President Barack Obama and Attorney General Eric Holder hasn’t stopped raiding marijuana dispensaries operating in states where sale of the drug is legal for medical purposes.

The nation’s leading medical pot advocacy group sets its sights on Pasadena’s dispensary ban

Dozens of medical marijuana dispensary operators and patients urged the City Council Tuesday to take another look at the ordinance that governs sales of the drug in Los Angeles, saying the current version would close more than 100 legitimate pot shops.

Operators of medical marijuana clinics appealed to the Los Angeles City Council on Tuesday to allow more clinics to stay open citywide, saying many facilities would otherwise just operate illegally.

Since the city ordered more than 600 medical pot shops to close last June, many of their former storefronts now stand vacant in a nearly moribund commercial real estate market hammered by the economic slump.

Aside from its outlaw image, one of the most vexing problems for medical marijuana is consistency. There are literally countless strains of the weed out there, and each one has different properties and effects.

A medical marijuana advocacy group sent letters Wednesday to about 140 California cities and counties that have banned pot dispensaries, including several in the Bay Area, and urged them to change their stance or face lawsuits.

Caren Woodson, director of government affairs at the patient advocacy group Americans for Safe Access (ASA) — who has five sick relatives who used marijuana as medicine — said that neighborhood dispensaries would keep needful patients out of situations in which they must obtain the pot illicitly.