The National Black Police Association yesterday became the latest group to endorse California’s Proposition 19, the November ballot measure that would make marijuana legal for adults 21 and older. From the Los Angeles Times: The National Black Police Assn., which has about 15,000 members, is the second African American organization to back the measure. The California NAACP has also endorsed it, citing the disproportionate arrest and incarceration of African Americans caught with marijuana. Ron Hampton,…