Former Rep. Tom Campbell has opened up a double-digit lead over his two rivals for the Republican U.S. Senate nomination, while Meg Whitman maintains a wide margin over Insurance Commissioner Steve Poizner in the GOP gubernatorial battle.


The results were part of a new Capitol Weekly/Probolsky Research poll conducted by Republican pollster Adam Probolsky with Democratic pollster Ben Tulchin in consultation. The complete survey is available here.


Whitman, a billionaire and former CEO of eBay, maintains a 28-point lead over Poizner, smaller than her lead in recent public polls. Whitman was the choice of 47 percent of likely Republican primary voters to Poizner’s 19 percent. More than one-third of Republican primary voters say they are still undecided, according to the survey.


By contrast, the most recent Field Poll showed Whitman with 63 percent of the vote compared to 14 percent for Poizner. In the Field survey, 23 percent of those surveyed said they were undecided.


The different numbers between this poll and recent public surveys reflect both timing and methodology. The poll was conducted from April 10-13, after Poizner began countering Whitman’s television ads with spots of his own.


“Poizner is just now developing his relationship with the voters,” said Probolsky. “He has been able to bring himself out of single digits in a couple of months, but  she’s still beating him more than two to one.”


Pollster Ben Tulchin says the results show some potential trouble for Whitman. “She’s ahead, but compared to other polling that’s out there, her numbers have dropped,” he said. “She’s spent a lot of money and she’s under 50 percent.”


Tulchin says Whitman is still the prohibitive favorite in the GOP primary, but “she’s going to have to sweat it out for the next two months. With candidates who are particularly new to the political process, Tulchin says, “voters always take a pause and say, ‘Let me reassess. Now that someone else has entered the stage, what’s going on?’ Going to be tough for Poizner, but it is a critical moment for the Whitman campaign.”


In the Senate race, former Congressman Tom Campbell was favored by 31 percent of respondents. Former Hewlett Packard CEO Carly Fiorina was next with 17 percent, followed by Assemblyman Chuck DeVore at 14 percent. More than 37 percent of those surveyed said they were still undecided.


Unlike the governor’s race, the U.S. Senate race has not seen a barrage of paid media activity. Campbell’s strength in the poll is, in part, due to his strong ballot designation as “economist/business educator,” says Probolsky.


“It also shows the strength of the Campbell name,” he said. “These types of academic, serious ballot titles seem to carry real weight with Republican voters.” But, Probolsky added, that could all be overwhelmed in the final weeks of the campaign.


Voters will head to the polls in less than six weeks, but voting will begin much sooner. Absentee ballots will be mailed to voters in less than three weeks -- a dynamic that could be critical, said Tulchin.


“In a primary, there’s higher percentage of voters who vote by mail, and Republicans vote more by mail than Democrats,” said Tulchin. “Taking those two factors into account -- you’re talking about 70-plus percent of voters getting their ballots in the mail in less than three weeks.”


Tulchin said that doesn’t mean all votes will be cast in the next few weeks, however.


“People tend to hold on to their ballots longer in contested races, but there’s going to be a surge of voting when people first get their ballots,” he said.


The poll did not measure any hypothetical general election match-ups in either the Senate or governor’s races. But respondents were asked one question about Whitman, Poizner and Jerry Brown. When asked which candidate for governor would be best when considering jobs and the economy, 33 percent of those surveyed said Brown, 31 percent said Whitman and Poizner was the choice of 9.2 percent.


Overall, the survey finds voters are a generally unhappy lot. More than 75 percent of those surveyed said California was on the wrong track. Just 14 percent of poll respondents said the state was on the right track.


The poll surveyed 751 likely voters from April 10-13. The poll has a margin of error of 3.7 percent.