Democratic Sen. Barbara Boxer declared victory over GOP rival Carly Fiorina on Tuesday night, ending one of the hottest, most fiercely contested and expensive Senate races in the nation.
Boxer thanked supporters in Los Angeles for giving her a victory "after the toughest and roughest campaign of my life."
"We're gonna win this race. I am thrilled," she said.
Fiorina, however, was not ready to concede as midnight approached.
"The facts are, it is too close to call," she told her volunteers at one point, promising them a long night of watching returns.
With 43 percent of the vote counted, Boxer had 50 percent of the vote to Fiorina's 45 percent.
The expected win for Boxer, 69, would give her a fourth term and buck the Republican tide that swept the nation.
Boxer led in opinion polls for most of the campaign, but the race remained close as she struggled to get more than 50 percent in many of them. The race aroused intense national interest, and both candidates ran negative and hard-hitting ads against each other.
With voters angry at Congress, Boxer shared the blame and found herself taking heat over the struggling economy and Washington's failure to reduce unemployment. Fiorina sought to capitalize on voters' unhappiness, saying Boxer had failed after serving 28 years in Congress, the past 18 in the Senate.
Fiorina, 56, the former head of Hewlett-Packard, had never run for public office before but cited her inexperience as an asset, saying her business background would be a good fit for Capitol Hill. Boxer portrayed Fiorina as a heartless CEO, criticizing her for laying off 30,000 employees and outsourcing thousands of jobs when she headed HP.
Fiorina, who began her long business career as a secretary, called Boxer an extremist who had done nothing of substance in Washington. She cast Boxer as a career politician and said her liberal politics made it impossible for her to reach across the aisle to work with Republicans.
Boxer had backing from President Barack Obama and first lady Michelle Obama, both of whom came to California to campaign for her. The president even did a radio ad on Boxer's behalf.
The candidates had two debates, feuding over abortion rights, immigration and tax policies, health care and whether the stimulus program passed by Congress last year had made any difference.
Boxer, one of the Senate's most vocal supporters of abortion rights, accused Fiorina of wanting to criminalize abortion. Fiorina opposed abortion rights and the Supreme Court decision that legalized abortion, but she said she did not want to turn women seeking abortions into criminals.
Boxer favored a comprehensive approach to immigration that included a pathway to citizenship for illegal immigrants. Fiorina backed an across-the-board extension of the tax cuts signed by President George W. Bush in 2001, while Boxer wanted to exclude the highest wage-earners.
The two sparred often over the $787 billion stimulus bill signed by Obama in an attempt to revive the economy. Fiorina called it a failure, saying it had done nothing to reduce California's unemployment rate, while Boxer called it a success, saying the economy would have gotten much worse without it.
Similarly, the two candidates disagreed on health care. Fiorina called for the repeal of the law passed by Congress in March, contending it would do nothing to lower costs, while Boxer said it would aid millions of Americans who lacked health insurance.
In Congress, Boxer has developed a reputation as a strong advocate for the environment and children. She is the only senator to head two committees, the environment and ethics panels.
She's a member of the Senate Foreign Relations Committee and was one of only 23 senators to vote against the war in Iraq. She favors the withdrawal of troops from Afghanistan beginning next summer.
Boxer began her long political career as a Marin County supervisor and served 10 years in the House before getting elected to the Senate in 1992. She received a score of 100 last year from the liberal group Americans for Democratic Action.
Fiorina missed two days of last-minute campaigning last week when she was hospitalized for an infection related to the reconstructive surgery she completed in July as part of her breast cancer recovery.
Some analysts said Fiorina hurt her prospects in the general election when she veered far to the right during the primary election in an attempt to woo conservatives. Fiorina challenged Boxer after surviving a primary challenge in June from former Rep. Tom Campbell and Assemblyman Chuck DeVore.
Boxer, meanwhile, had a tougher race than gubernatorial candidate Jerry Brown because voters were particularly angry with Congress, political experts said.
Tony Quinn, co-editor of the California Target Book, which analyzes legislative and congressional races, said Boxer had to run in a year of "a monumental Republican tide."
"It is driven by economic unhappiness and a sense of disappointment in President Obama that has even stretched into nice, blue California," he said. " They are blaming Congress, and Boxer is a major chair of a major committee."