California Democratic Sen. Barbara Boxer has widened her lead over Republican challenger Carly Fiorina, according to a Field Poll released Friday.
The survey showed Boxer leading Fiorina 47 percent to 41 percent, with 12 percent of voters undecided. A July Field Poll showed Boxer with support from 47 percent of voters, compared to 44 percent for Fiorina, a gap that was within that poll's margin of error.
"I would surmise much of this has to do with the advertising that the Boxer campaign has done," Field Poll Director Mark DiCamillo said. "It has had the intended effect."
Boxer enjoyed a 12-to-1 cash advantage over Fiorina in the latest campaign reports, made public early in the summer.
Boxer began running advertisements Sept. 13, the day before polling began for the survey, while Fiorina did not launch her first statewide TV ad until Thursday. Boxer opened with a television ad highlighting her accomplishments in Congress, then released an ad accusing Fiorina of enriching herself as a corporate executive while laying off thousands of workers at Hewlett-Packard Co. and shipping jobs overseas.
Fiorina's first ad of the general election attacks Boxer's "arrogance" when she asked an Army Corps of Engineers general during a committee hearing to call her "senator," rather than "ma'am."
The poll surveyed 857 registered voters from Sept. 14 to Sept. 21 and has a margin of error of 4.1 percentage points. Among likely voters, the poll has a sampling error of 5.8 percentage points.
For Fiorina supporters, the November election is shaping up as a referendum on Boxer, who is seeking a fourth term in the Senate.
Two-thirds of Fiorina's supporters said they are motivated more by their dislike of Boxer than their enthusiasm for Fiorina.
Unlike GOP gubernatorial candidate Meg Whitman, who has made inroads with women and Hispanics, Boxer has maintained the lead among those groups. Likely female voters favor Boxer 46 percent to 40 percent. The senator has 48 percent support among likely Hispanic voters, compared to 29 percent for Fiorina.
That means Fiorina will have to get independent voters to turn out for her in November, DiCamillo said. The Field Poll found independents favoring Boxer 46 percent to 40 percent over Fiorina, with 14 percent of them undecided.
"The path to success for Fiorina will probably be somewhat different than for Whitman," DiCamillo said. "Fiorina has less of an opportunity just because her stances really run counter to where most Democrats are. In my judgment, she's going to have to win nonpartisans by double-digit margins."
Democrats have a registration edge in California of about 13 percentage points.
© 2010 The Associated Press.