California's marijuana legalization proposition is facing increasing opposition from the Obama administration, including a visit to the state by the drug czar to urge voters to oppose it.

Gil Kerlikowske , the drug czar and former Seattle PD chief, visited a Pasadena recovery center, where he acknowledged the war on drugs hasn't succeeded and a new approach should focus on prevention and treatment, reports the Los Angeles Times.

The prior week, U.S. Attorney General Eric Holder said he would "vigorously enforce" federal narcotics laws, even if voters approved Proposition 19 on Nov. 2. Holder said he "is considering all available legal and policy options."

Law enforcement in the state has lined up against the measure, actively participating in the No-on-19 group Public Safety First . Recreational marijuana use involving fatal crashes will increase should the measure pass, according to the group.

Notable exceptions include the retired officers of Law Enforcement Against Prohibition (LEAP) and National Black Police Association who support it.

Earlier this month, a group of prominent law professors came out in support of the measure with an open letter calling the country's marijuana prohibition a "wasteful and ineffective policy" that has "clogged California's courts alone with tens of thousands of non-violent marijuana offenders each year."

The measure would allow Californiana 21 years and older to grow and possess the drug. It would also authorize local governments to approve sales, cultivation and taxes on the drug.

Proposition 19 is trailing in the polls with 39% support, according to a new poll by the Los Angeles Times and University of Southern California.

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