Four of California's best-known candidates for governor threatened to boycott the only debate Arnold Schwarzenegger (search) has agreed to attend unless the format -- which they describe as scripted -- is scrapped for a more spontaneous exchange of ideas, senior campaign aides told Fox News.

The debate will be broadcast by more than 100 California television and radio stations and is expected to reach tens of millions of viewers and listeners. No other debate promises an audience of this size.

Richie Ross, campaign manager for Lt. Gov. Cruz Bustamante (search) told Fox News that the four candidates for governor drafted the letter to the California Broadcasters Association, the sponsor of the Sept. 24 debate.

Before sending it to the association, the candidates sent it to Arnold Schwarzenegger's campaign, seeking its signature. Top aides to state Sen. Tom McClintock (search) told Fox News the letter was designed to increase pressure on Schwarzenegger to agree to more debates.

The candidates seeking a new format are: Lt. Gov. Cruz Bustamante, GOP state Sen. Tom McClintock, Green Party candidate Peter Camejo, and independent candidate Arianna Huffington.

Until now, the broadcasters association format has long been known and produced scant controversy. The association has already released the questions it will pose to the candidates.

Stan Statham, president of the broadcasters association, said he had not received the letter and wonders if it will actually arrive.

"Until I see it in my hands, I won't believe it," Statham told Fox News. "One or more of the candidates or their consultants are playing games."

Statham said the format would stay, regardless of the last-minute protest.
"It's not up for review, re-negotiation or debate," Statham told Fox News. "We're not moving."

The format calls for 12 questions to be posed to the five candidates. Each question was drawn from those submitted by California voters. The association will videotape the questioner and then play the question for one candidate. The format then allows for up to 90 seconds of answers and unrehearsed follow-up questions from the other candidates. The debate allows for at least 60-65 minutes for answering questions and roughly 20-25 minutes for closing statements.

Ross told Fox News that the four candidates are now seeking an alternate venue for the new debate if the format is not changed. Ross said they intend to hold the alternate debate on the same day.

Statham told Fox News he resents criticism that the debate format is scripted.
"It's absolutely not scripted, by this stage of the campaign, candidates who've made it this far are already scripted," Statham said. "We went out of our way to break the question-rebuttal format. We wanted some sizzle in the debate. If these candidates are giving rhyming, whoop-dee-doo sound bites, they're not going to cut it with the voters. We wanted some sizzle in the debate."

Schwarzenegger's campaign said that they will attend the broadcasters debate.
"We haven't seen the letter," spokesman Todd Harris said. "But my inclination is to say we won't sign it. We're looking forward to the debate. We hope all the candidates who have accepted invitations will in fact show up. It's unfortunate these other candidates are already talking about backing out."

Statham said Schwarzenegger's camp sent a letter recently asking the organization not to release the questions ahead of time, to avoid the appearance that he needed to have the questions provided in advance. Statham said that the association rejected the request because it wants the voters to know what the questions will be, so they can judge the clarity of the responses and the agility of candidates to respond when challenged.

Harris dismissed the threatened boycott as a "cheap ploy" and "temper tantrum." He said Schwarzenegger would appear at the debate and take all the time allotted to answer voter questions. If the others fail to attend, Harris said Schwarzenegger would gladly monopolize a debate broadcast to millions of Californians.