Democratic Sen. Barbara Boxer has opened up a six-point lead against her GOP opponent, Carly Fiorina, as the race heads into the final six weeks, according to a Field Poll released Thursday.
Boxer, a three-term incumbent, leads 47 percent to 41 percent. She led by three points in July.
The poll found that impressions of Boxer are sharply divided and highly partisan, with 93 percent of all likely voters having an opinion of her. It found that Boxer still has a high unfavorable rating of 48 percent. But it has declined from a high of 52 percent two months ago.
"She's hanging in," said Mark DiCamillo, the poll's director. "It looks like she's had a pretty good month or two."
DiCamillo attributed the results to Boxer's television advertising, which began last week, while Fiorina unveiled her first television ad on Thursday. DiCamillo noted that Fiorina's unfavorable rating has jumped from 29 percent to 38 percent since July.
"Fiorina has definitely taken a hit," he said.
John Armstrong, 65, a retired computer programmer and a Democrat from Roseville, said he planned to vote for Boxer because she has worked hard to protect the California coastline from oil development, and she favors tax policies that benefit the middle class over the wealthy.
"She's not in the front all the time, but I think she does a good job in the background," said Armstrong, one of the poll's respondents.
The poll found that most respondents are basing their choices on how they feel about Boxer. Among Boxer supporters, 67 percent said their vote is more a vote for Boxer than it is a vote against Fiorina. And 65 percent of those who supported Fiorina said their preference is more a vote against Boxer than it is a vote for Fiorina.
Elizabeth May, 39, a Republican poll respondent from Gridley, said she planned to vote for Fiorina mainly for one reason: "She's not Barbara Boxer." She said she didn't know much about Fiorina, but she disliked Boxer's advocacy of gun-control laws.
Democrats, who are expected to represent 44 percent of likely voters in November, backed Boxer by 76 percent to 11 percent. Republicans, who are expected to account for 35 percent of all likely voters, picked Fiorina 79 percent to 10 percent.
Joseph Wilson, 94, a Democratic poll respondent from Sacramento, was among the likely voters who said he'll probably cross party lines, as he has in the past. He said he's undecided, but he'll probably vote against Boxer.
"Frankly, I don't like her just from when I've seen her talk on TV," he said.
Nearly one in six, or 18 percent, who participated in the poll said they identify a lot with the tea party movement.
Those voters favored Fiorina by a 92 percent to 2 percent margin.
Boxer posted a lead of more than 2 to 1 among voters in the Bay Area, and she had single-digit leads in Los Angeles County and in Northern California counties outside the Bay Area. Fiorina led in the Central Valley and in Southern California areas outside of Los Angeles County.
The poll found few differences by gender and race in support for the candidates.
While the Field Poll found a dead heat between gubernatorial candidates Democrat Jerry Brown and Republican Meg Whitman, DiCamillo said the Senate race and governor's race are "two very different contests." Unlike Fiorina, he said, Whitman has had success cutting into support among traditional Democratic constituencies, such as women, Latinos and voters in Los Angeles County.
If Fiorina is to win, he said, she'll need to fare better among independent voters, who backed Boxer 46 percent to 40 percent.