A new study released today shows conclusively that in California’s largest cities African-Americans are arrested for marijuana possession at much higher rates that whites. In the 25 cities profiled, African-Americans were arrested at four to 12 times the rate of whites, despite much higher use rates among whites. This horrifying disparity is one reason Proposition 19 has earned the support of civil rights groups, including the California NAACP and the League of United Latin American Citizens of California.…