Gov. Arnold Schwarzenegger signed a law late Thursday that reduces possession of an ounce or less from a misdemeanor to an infraction, with a maximum punishment of a $100 fine.
Even as a misdemeanor, possession of up to an ounce of pot was still punishable only by a $100 fine and no jail time. But offenders also faced arrest, a possible court appearance and a criminal record.
Schwarzenegger said after signing Senate Bill 1449 that he does not support decriminalization of marijuana, but the law would save the state courts money.
"In this time of drastic budget cuts, prosecutors, defense attorneys, law enforcement and the courts cannot afford to expend limited resources prosecuting a crime that carries the same punishment as a traffic ticket," the governor said in a statement.
The bill authored by San Francisco Democratic Sen. Mark Leno was supported by the Judicial Council of California -- the official policymaking body of the court system -- and by the California District Attorneys Association.
California's major police associations all opposed the legislation.
Opponents said reducing possession to an infraction would discourage people cited for the offense from seeking state-funded drug treatment as provided for drug offenders under a ballot measure passed in 2000.
The governor signed the pot law as state voters prepare to weigh in on a closely watched ballot measure to legalize marijuana for recreational use -- a measure Schwarzenegger opposes.
Proposition 19 would more or less make the new law irrelevant by legalizing possession of up to an ounce for personal use for adults 21 and older.
Nevertheless, marijuana advocates praised the change enacted by the bill as they pointed to the spike in misdemeanor marijuana arrests in the state in recent years.
"Californians increasingly recognize that the war on marijuana is a waste of law enforcement resources," said Dale Gieringer, director of the California chapter of the National Organization for the Reform of Marijuana Laws and co-author of the state's landmark medical marijuana law.
Authorities made more than 61,000 arrests for marijuana-related misdemeanors in 2008, the latest year for which data exists, California Department of Justice records show.
In the prior decade, such arrests averaged about 48,000 until 2006, when the figure exceeded 50,000 for the first time.