los angeles supporters drive legalize recreational marijuana adults california say wednesday collect enough signatures qualify measure november ballot formally launch campaign win voters democratic lieutenant governor gavin newsom lead coalition supporters include billionaire high-tech entrepreneur sean parker say campaign gather 600,000 petition signatures well 365,880 minimum require signatures must still officially certify state election officials rest assure november ballot newsom tell san francisco news conference kick efforts build voter support initiative initiative dub adult use marijuana act would allow individual age 21 old possess use much ounce marijuana private recreational use permit personal cultivation many six marijuana plant measure would also establish system license regulate tax sales marijuana allow city governments exercise local control disallow commercial distribution within border opinion poll show attitudes shift favor liberalize marijuana laws since california voters defeat recreational cannabis initiative 2010. california lead way legalize marijuana medical purpose 1996 22 state district columbia follow suit although cannabis remain classify illegal narcotic u.s. law voters four state colorado washington oregon alaska plus district columbia go step since 2012 permit recreational use adults opponents liberalize marijuana laws argue measure carry major public safety risk would make pot accessible youngsters supporters california initiative say measure include number provision aim keep marijuana hand minors include ban market children explicit warn label cannabis products safe-packaging restrictions also say hundreds millions dollars state tax revenue pot sales would earmark substance abuse prevention treatment law enforcement research one key organization back late ballot measure naacp civil right group embrace argument current marijuana laws lead disproportionate number minorities incarcerate minor drug offenses pot legalization supporters launch california ballot campaign