Gov. Arnold Schwarzenegger on Thursday signed into law a change to California's marijuana laws that some describe as a reduction of criminal penalties and others are describing as being effectively decriminalization.

The move comes a month before California voters decide on Proposition 19, a ballot initiative that would fully legalize, regulate and tax marijuana in the state -- a move the governor opposed even as he signed the new bill into law.

Under the new legal regime, marijuana possession will be a civil infraction, like a speeding ticket, and will be punishable by a $100 fine. Previously, possession was a misdemeanor, even though the penalty was the same -- a $100 fine, with no jail time possible.

For some observers, this is a de facto decriminalization, as marijuana possession would no longer be reflected in a criminal record. But, as CBS News notes, the fundamental change will be that those who are issued a ticket for marijuana possession will no longer have the ability to challenge the charge in court.

"Notwithstanding my opposition to Proposition 19 ... I am signing this measure because possession of less than an ounce of marijuana is an infraction in everything but name," Schwarzenegger wrote in his signing statement. "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's move is being opposed by many of the same activists who are campaigning against Proposition 19.

"This virtual legalization of marijuana definitely sends the wrong message to teenagers and young adults," said Randy Thomasson, president of, as quoted at the LA Times. "It invites youth to become addicted to mind-altering pot because there's not much hassle and no public stigma and no rehab if they’re caught."

Not surprisingly, the governor was praised by Dale Gieringer, director of California NORML, which supports legalization.

"Gov. Schwarzenegger deserves credit for sparing the state's taxpayers the cost of prosecuting minor pot offenders," said Dale Gieringer, head of the California branch of NORML. "Californians increasingly recognize that the war on marijuana is a waste of law enforcement resources."

With a month left before the mid-term elections, polls show the momentum is with the pro-legalization crowd, at least for the time being.

A poll last week showed California voters backing Prop 19 by a margin of 49 to 41. A more recent poll showed voters backing the initiative by a margin of 52 to 41 -- a significant number, as it would mean the initiative would pass even if all undecideds voted against it.

Bay Area Indymedia reports that Prop 19 is "polling better than any candidate or initiative on California's ballot."