State election officials said Nader fell far short of the 153,035 signatures needed by Friday's deadline. He submitted 82,923 with 56 of the state's 58 counties reporting, said Lauren Hersh, a spokeswoman for the secretary of state's office.
Nader's campaign coordinator in California, Forrest Hill, said he thought the final tally was "closer to 100,000."
"It was very difficult collecting these signatures, as you can imagine," he said Saturday. "We tried to get some help, but the paid signature gatherers did not work for more than a week or two. They all quit. They said it was too abusive, the attacks that went on" from people opposed to Nader's candidacy.
Hill said the campaign was trying to convince Green Party members in California to dump David Cobb, a Eureka lawyer, as their presidential nominee and substitute Nader, who was the Green Party presidential candidate in 2000. But Hill conceded that effort was a long shot.
"We have to have a general assembly and need 80 percent of the delegates to decide to dump Cobb and put Nader-Camejo on the ballot," he said, referring to Peter Camejo, Nader's running mate. "That's probably a high test. A lot of people are probably afraid of the ramifications. It could result in disaffiliation from the national party."
The Greens have until Aug. 26 to decide which candidate they want on the ballot in California, said Hersh.
Beth Moore Haines, a spokeswoman for the Green Party of California, said changing nominees was highly unlikely.
"I think there would be considerable cost to California in good will toward the rest of the Greens in the nation, if we did something like that," she told The Sacramento Bee. "The hope is always that folks with similar values on different campaigns work as cooperatively as they can. But this would be one of the less collaborative strategies, and not one embraced by the Greens in California."
Hill said the Nader campaign could also try to get Nader on the ballot by going to court to challenge the state's signature threshold for independent candidates.
The Nader campaign says it expects its ticket to appear on ballots in more than 43 states, the same number Nader was on four years ago.
Nader received only 2 percent of the California vote in a Field Poll released this week. Democratic nominee John Kerry led President Bush 51 percent to 40 percent in that survey of 633 likely voters. The margin of error was 4.1 percent.