By Adam Nagourney, New York Times

LOS ANGELES — Let Colorado and Washington be the marijuana trailblazers. Let them struggle with the messy details of what it means to actually legalize the drug. Marijuana is, as a practical matter, already legal in much of California.

No matter that its recreational use remains technically against the law. Marijuana has, in many parts of this state, become the equivalent of a beer in a paper bag on the streets of Greenwich Village. It is losing whatever stigma it ever had and still has in many parts of the country, including New York City, where the kind of open marijuana use that is common here would attract the attention of any passing law officer.

“It’s shocking, from my perspective, the number of people that we all know who are recreational marijuana users,” said Gavin Newsom, the lieutenant governor. “These are incredibly upstanding citizens: Leaders in our community, and exceptional people. Increasingly, people are willing to share how they use it and not be ashamed of it.”

Marijuana can be smelled in suburban backyards in neighborhoods from Hollywood to Topanga Canyon as dusk falls — what in other places is known as the cocktail hour — often wafting in from three sides. In some homes in Beverly Hills and San Francisco, it is offered at the start of a dinner party with the customary ease of a host offering a chilled Bombay Sapphire martini.

Lighting up a cigarette (the tobacco kind) can get you booted from many venues in this rigorously antitobacco state. But no one seemed to mind as marijuana smoke filled the air at an outdoor concert at the Hollywood Bowl in September or even in the much more intimate, enclosed atmosphere of the Troubadour in West Hollywood during a Mountain Goats concert last week.

Arnold Schwarzenegger, the former Republican governor, ticked off the acceptance of open marijuana smoking in a list of reasons he thought Venice was such a wonderful place for his morning bicycle rides. With so many people smoking in so many places, he said in an interview this year, there was no reason to light up one’s own joint.

“You just inhale, and you live off everyone else,” said Schwarzenegger, who as governor signed a law decriminalizing possession of small amounts of marijuana.

Some Californians react disdainfully to anyone from out of state who still harbors illicit associations with the drug. Bill Maher, the television host, was speaking about the prevalence of marijuana smoking at dinner parties hosted by Sue Mengers, a retired Hollywood agent famous for her high-powered gatherings of actors and journalists, in an interview after her death last year. “I used to bring her pot,” he said. “And I wasn’t the only one.”

When a reporter sought to ascertain whether this was an on-the-record conversation, Maher responded tartly: “Where do you think you are? This is California in the year 2011.”

John Burton, the state Democratic chairman, said he recalled an era when the drug was stigmatized under tough antidrug laws. He called the changes in thinking toward marijuana one of the two most striking shifts in public attitude he had seen in 40 years here (the other was gay rights).

“I can remember when your second conviction of having a single marijuana cigarette would get you two to 20 in San Quentin,” he said.

In a Field Poll of California voters conducted in October 2010, 47 percent of respondents said they had smoked marijuana at least once, and 50 percent said it should be legalized. The poll was taken shortly before Californians voted down, by a narrow margin, an initiative to decriminalize marijuana.

“In a Republican year, the legalization came within two points,” said Chris Lehane, a Democratic consultant who worked on the campaign in favor of the initiative. He said that was evidence of the “fact that the public has evolved on the issue and is ahead of the pols.”

A study by the California Office of Traffic Safety last month found that motorists were more likely to be driving under the influence of marijuana than under the influence of alcohol.

Still, there are limits. No matter how much attitudes in California may have changed, it remains illegal in most of the country — as Californians have been reminded by a series of crackdowns by the Justice Department on medical marijuana here. People who use the drug recreationally, who said they would think nothing of offering a visitor a joint upon walking through the door, declined to be quoted by name, citing the risks to career and professional concerns.

That was the case even as they talked about marijuana becoming commonly consumed by professionals and not just, as one person put it, activists and aging hippies. Descriptions of marijuana being offered to arriving guests at parties, as an alternative to a beer, are common.

In places like Venice and Berkeley, marijuana has been a cultural presence, albeit an underground one, since the 1960s. It began moving from the edges after voters approved the legalization of medical marijuana in 1996.

That has clearly been a major contributor to the mainstreaming of marijuana. There is no longer any need for distasteful and legally compromising entanglements with old-fashioned drug dealers, several marijuana users said, because it is now possible to buy from a medical marijuana shop or a friend, or a friend of a friend growing it for ostensibly medical purposes.

That has also meant, several users said,¸that the quality of marijuana is more reliable and varied, and there are fewer concerns about subsidizing a criminal network. It also means, it seems, prices here are lower than they are in many parts of the country.

Newsom — who said he did not smoke marijuana himself — said that the ubiquity of the drug had led him to believe that laws against it were counterproductive and archaic. He supports its legalization, a notable position for a Democrat widely considered one of the leading contenders to be the next governor.

“These laws just don’t make sense anymore,” he said. “It’s time for politicians to come out of the closet on this.”