At a December fund-raiser for Eliot Spitzer, an advertising-agency veteran emboldened by three glasses of red wine marched up to the attorney general and told him he could help him get elected.

The man’s name was James “Jimmy” Siegel, a well known figure in the industry who had just spent two decades at BBDO climbing the Madison Avenue food chain from junior copywriter to vice chairman. Known for his slick, funny, high-profile ads, he wrote the Super Bowl spot for Visa featuring a hapless Bob Dole missing his ID, and the “Yo, Yao” ad starring the giant Chinese basketball player.

Mr. Spitzer had been approached by political consultants who were hungry for business and was wary of another pitch. “He looked at me like, ‘Who the hell are you?'” Mr. Siegel said, recounting his conversation.

A half a year later, Mr. Siegel has become a crucial component of Mr. Spitzer’s election efforts. He’s the brains behind Mr. Spitzer’s $10 million ad campaign, whose stylized and poignant appeal has attracted some nationwide notice. Some of the Democratic Party’s leading lights, like Rep. Rahm Emanuel, Senator Clinton, and Governor Cuomo, have personally complimented him on his ads, Mr. Siegel said. Governors have tried to hire him, and he’s planning a political advertising business that will cater mostly to Democrats.

“Jimmy’s work is thoughtful, sharp, and different,” said Mr. Spitzer’s campaign manager, Ryan Toohey.

Less impressed are political consultants, who say Mr. Siegel is a political amateur who would be lost if the governor’s race became competitive. His ads simply “reinforce existing imagery,” said Hank Sheinkopf, a political consultant who created ads for Mr. Spitzer’s 1998 campaign. “They are competent. Am I overwhelmed by the production? The answer is no.”

For Mr. Sheinkopf and other consultants, Mr. Siegel is the latest attempt by a cocky advertising executive to move into their turf. “They look down on us, and we don’t pay attention to them,” Mr. Sheinkopf said.

In background and style, Mr. Siegel, who wears his hair slicked back and sports a goatee, could hardly be more different from his boss. Mr. Spitzer, the son of a wealthy real estate developer, went to Princeton. Mr. Siegel worked his way through CUNY’s York College by driving a taxi. But like Mr. Spitzer, he’s a lifelong Democrat and a critic of the Bush administration, which he says is “basically lying to you on a daily basis.” Mr. Siegel in December quit his job to focus on his true love, writing thrillers. His book, “Derailed” (Warner Books), was turned into a movie starring Jennifer Aniston, and his fourth book, “Deceit,” which is about a lying journalist in the Stephen Glass mold who can’t get anyone to believe him when he uncovers a true scandal, is coming out next month.

Mr. Siegel was no longer pitching products but was eager to help out the Democratic Party by pitching candidates. And like many in the ad industry, he had more than a healthy contempt for the quick-and-dirty methods of political consultants.

“I always felt that political advertising was just dreadful,” he told The New York Sun in an interview. “I didn’t know why it was dreadful. I just knew that it was.” The typical political ad is a candidate standing in front of a statehouse and screaming at the viewer, Mr. Siegel said, describing an ad produced by Mr. Spitzer’s Democratic challenger, Nassau County executive Thomas Suozzi. To him, the one that stands out is Ronald Reagan’s “It’s Morning in America” campaign, and that was the work of Phil Dusenberry of BBDO.

Mr. Siegel told Mr. Spitzer that he could do better than the rest of the pack – and for no charge. “Unbeknownst to me, Eliot had been feeling much the same way about political advertising,” Mr. Siegel said.

After Mr. Siegel had a few meetings with Mr. Spitzer’s staff and the candidate’s wife, Mr. Spitzer gave Mr. Siegel and his chosen production company, Moxie Pictures, a green light.

“Voice,” the first spot he created for Mr. Spitzer and geared toward upstate New Yorkers, set the tone for the campaign by confounding assumptions about what a political ad should be. It begins with two plaintive notes on the piano as blackness dissolves to a close-up of a youngish woman standing in the spare front yard of an apparently middle-class suburban home where a little boy plays in the background. The piano is joined by weeping strings, as the woman’s gaze floats upward to camera level, like she’s catching the viewer’s glance and making intimate eye contact. She’s not smiling, nor frowning, but appears almost angelic, like she’s a ghost communicating a heartfelt message. The expression has a label – “soulful,” according to Mr. Siegel – and it’s worn by almost every “typical” New Yorker who appears in the ad in images that are drained of color and somehow more solemn.

“For every New Yorker whose husband or child has to go somewhere else just to get a job,” says a male announcer. “For every New Yorker drowning in property taxes … For every New Yorker who’s been ignored … left out … who’s been told you can’t fight City Hall so many times they’ve come to believe it … For every New Yorker without a voice … Listen … There’s one strong enough for all of us.”

The inspiration for the refrain was what Mr. Siegel considers to be one of the most effective political speeches ever, the farewell of Tom Joad, played by Henry Fonda, in “The Grapes of Wrath.” Mr. Spitzer is cast as Joad, who vowed he would be everywhere for the underdog.

Mr. Spitzer is absent from the entire ad, except in the final second seconds of the spot when the picture darkens and the attorney general’s disembodied voice fills the void: “I represent the people of the State of New York,” the Spitzer voice says. “It was more dramatic not to see him but to hear him,” Mr.Siegel said.

The accumulative effect of the yearning faces,the lyrical music,and the message of despair and hope is a 30-second spot that has a strange emotional pull. You might not have any idea who the attorney general is, but it’s still moving. “A good commercial should touch you viscerally,” he said.” You want people to feel something, but you don’t want to get saccharine or mawkish.”

Mr. Siegel designed each ad to have a specific emotional effect. “Newsmakers” features actual clips of newspaper articles about Mr. Spitzer that explode onto the screen with a boom and retreat into the distance. Mr. Siegel said the effect “was to get a sense of the sheer number of things he accomplished.” In two ads Mr. Spitzer talks in person, but he doesn’t make eye contact with the viewer. Again, that’s on purpose: “When he looks at camera, he’s making a speech,” he said. “When he’s looking slightly off camera, he’s having a conversation.”

In another ad, called “Tribute,” which is composed of a series of iconic images of New York (one of Niagara Falls is actually Canada) that are supposed to make the viewer feel nostalgic for the Empire State’s gloried past, the spot concludes with a black-and-white photo of Mr. Spitzer at a podium, with his head bowed in contemplation. Normally, an ad would feature a candidate smiling, but Mr. Siegel wanted to aim for something more iconic.” I call that my Robert Kennedy homage shot,” he said.

Mr. Spitzer, he says, was a little uncomfortable with the ad. According to Mr. Siegel, he wondered: “Is this making me seem greater than I really am?”

Mr. Siegel told the attorney general not to worry. “In his case, I don’t think we’ve been over the top,” he said.