A leaked poll that appears to show Sonoma County Supervisor Mike McGuire with a commanding lead in the race for the North Coast's state Senate seat was criticized Tuesday by other candidates as deliberately misleading.

The dust-up is a preview of what could be a bruising contest for the 2nd District Senate seat. With the election a year away, accusations already are flying over what some perceive as dirty politics on the part of anonymous operatives.

Jim Moore, the Sacramento-based pollster whose survey of 400 North Coast registered voters two weeks ago has roiled the campaigns in the Senate race, Tuesday declined to say who paid for the survey.

Moore said it was not anyone affiliated with the three candidates who are so far entered in the race. He also said the results, despite being widely circulated, were not supposed to become public.

"Our intent was to get a read on the state of the race, Lehman versus McGuire, or anybody," said Moore, who has a long track record of conducting public opinion surveys in Sonoma County, mostly on issues related to transportation.

Three candidates so far are seeking to replace Sen. Noreen Evans, D-Santa Rosa, who is voluntarily stepping down in 2014 to practice law. Voter registration in the district spanning seven counties is heavily Democratic. The majority of its more than 1 million residents are centered in the more urbanized south, including Sonoma and Marin counties.

The poll showed McGuire garnering 30 percent of the vote, compared to four percent for Chris Lehman, an Arcata political consultant and fundraiser, and three percent for Eric Lucan, a Novato city councilman.

McGuire achieved an even higher percentage of the vote — 48 percent — after survey respondents were given information about his background. Lehman and Lucan drew a combined 20 percent, and a hypothetical Republican candidate polled at 18 percent. About 14 percent were undecided or had no opinion.

Santa Rosa City Councilwoman Erin Carlstrom, who has dropped out of the race, was not included in the poll.

David McCuan, a political scientist at Sonoma State University, said the poll highlights McGuire's strength.

"It's too soon to say it's his race to lose. But clearly, he's the favorite," McCuan said.

McCuan speculated that someone with deep pockets paid for the poll. He said the timing suggests that the goal was to discourage other candidates from entering the contest, or to show donors from outside the North Coast region where to direct their financial support.

"This race should be expensive, highly charged, and receive a lot of attention far beyond the political corridors of Sacramento," McCuan said.

McGuire on Tuesday said his campaign had no involvement with the poll. He declined to say whether he thought it amounted to dirty politics.

"Any analysis of the poll should be left up to political pundits and political consultants. I'm focused on my job as county supervisor," McGuire said.

The other campaigns in the race, however, attacked the poll on a number of fronts.

The survey included responses from about 400 people living in five of the seven North Coast counties that comprise the 2nd Senate district. Trinity and Del Norte counties were excluded.

Critics questioned how the poll could show so much support for McGuire, when 88 percent of respondents said they had not heard of him or had no opinion of him. Nearly 100 percent said the same of the other two candidates, and yet both men garnered some support in the category of who people were likely to vote for.

"As an instrument to offer a reliable snapshot of the race as it exists today, the poll is a failure," political consultants Lisa Gasperoni and Mark Capitolo wrote in an email on behalf of Lehman.

Critics also said pollsters included incomplete or misleading information about Lehman and Lucan when posing questions to survey respondents.

Lehman, for instance, was described as a "political adviser" and a "political fundraiser" with ties to "Senate Leadership in Sacramento." His campaign complained that the poll didn't include any of his other attributes, such as his efforts to combat smoking and close corporate tax loopholes in California, or the fact he is a father of three, including of a daughter who has a rare congenital heart defect.

"The poll is meaningless except that it shows none of the candidates in this race has a real strong following. Everything else was basically a fiction created by the pollster," Lehman said.

The survey reported that 99 percent of respondents living in Lehman's home territory of Humboldt County had never heard of him or had no opinion of him.

McCuan called the response from Lehman's camp "an attempt to put a spin on numbers that should be more favorable for someone who has worked in a community for some time."

"However, supporters of Lehman are correct to point out that the labels used in the poll and the questions are geared to moving voters against Lehman towards someone like McGuire," McCuan said.

Twenty percent of survey respondents living in Sonoma County had a favorable opinion of McGuire. Six percent did not, and another 74 percent had not heard of him or had no opinion.

McCuan called Lucan a "nonfactor" in the race based on the survey results.

Lucan declined to be interviewed. Leo Wallach, his political consultant, issued a statement saying the poll "sheds very little light on the campaign at this point."

"When the candidates are eventually described in the poll, there is nothing about Eric Lucan's service to the city of Novato and the North Bay region, his strong business background, or his extensive work for local youth and the community. It simply is not reflective of the campaign we will run," Wallach said.

You can reach Staff Writer Derek Moore at 521-5336 or derek.moore@pressdemocrat.com. On Twitter @deadlinederek.