Barbara Boxer, the senator from California, leaned over her press secretary, Peter True, as he sat at an HP desktop computer and tried to find an old campaign ad from 2010.

Boxer wanted me to see the ad because it featured interviews with former employees of HP who had been laid off by the storied technology company’s one-time CEO, Carly Fiorina, who in 2010 challenged Boxer for her seat and now, five years later, seeks the Republican nomination for a somewhat higher office: president of the United States.

“Oh! That’s great!” Boxer said when I noted the make of the computer. “I love HP!”

True looked bemused. “It’s a great California company,” he said.

He scrolled through a page of thumbnails as Boxer leaned in closer to the screen. “These are not right,” she said. “No, it’s a man’s face. It’s none of these.”

We sat back down on the sand-colored couches as True continued to scroll. “When you know people, you know a pattern of a person,” Boxer said. Fiorina’s pattern, the senator cautioned, “is hurting other people in order to move herself up the ladder.”

For Boxer, who defeated Fiorina by 10 points—or as she likes to point out, by 1 million votes—in 2010, ensuring that the former CEO gets no closer to the White House than she did to the Senate has become an unexpected end-of-career crusade.

Boxer, a self-described “big Hillary Clinton supporter,” announced in January that she would not be seeking reelection in 2016, after 22 years in the Senate. In her remaining time, she told me, she had a list of things that she wanted to do, working on legislative issues while she still could and finishing her memoirs (she’s already published two novels) chief among them.

Not on the list at the time was spending her idle hours talking to reporters like this one about a Senate race she won five years ago against a candidate she regards about as highly as the seasonal flu.

“I had a very full plate, and then when she decided to run!” Boxer burst into laughter at the very idea. “People started calling me, ‘What do you think?’” What she thought, she said, was “this is a new definition of chutzpah.”

After all that had been revealed about Fiorina’s record at HP and how badly she was defeated, Boxer said, “I thought, how could she possibly think that she could now do this?” Of course, she noted, anyone has the right to run for president, but really, the chutzpah.

“This is yet another issue I have to talk about because I love my country so much,” the senator said. “I need people to know who this woman is and what her pattern is of hurting people, stepping on them, and then rewarding herself.”

Boxer said she first became aware of Fiorina in 1999, when she was named CEO of HP, but didn’t meet her until sometime later, when they both attended an event for women in Silicon Valley. Boxer couldn’t remember exactly when it was, but it was a while before 2010. “I didn’t have much of an impression,” she said. “I went up to her and I said how proud I was to see a woman in this position, and she didn’t seem that interested in a dialogue.”

When Fiorina entered the Republican primary in 2009, Boxer said she observed, with some concern, how Fiorina treated her opponent, Tom Campbell. “She turned him into a demon,” she said, referring to the Internet-infamous “Demon Sheep” ad wherein Fiorina accused Campbell of being an “FCINO,” code for “fiscal conservative in name only.”

As illustration, Fiorina used a man dressed in a sheep costume with glowing, beady red eyes. “It became a viral hit,” Boxer remembered, sounding horrified. “Turning your opponent into a demon! Especially a nice guy like Tom!”

“It was pretty tough,” she added. “So I knew if she won, lord knows what I was gonna get.” Boxer laughed when she said that, but she acknowledged Fiorina was a tough opponent. “She did turn out to be—out of the 12 elections I’ve won, and I’ve won 11 straight—by far and away the most negative campaigner I’ve ever run against.”

Fiorina mocked Boxer for her concern over climate change, saying she was “worried about the weather” when there were bigger fish to fry, like terrorists, and branded the senator a hypocrite for giving a speech to Cisco, a company that had outsourced jobs to other countries, even though Boxer’s central gripe with Fiorina was that she had outsourced jobs while at HP. Fiorina also criticized Boxer’s appearance—though that wasn’t supposed to be public. She was caught by a hot mic saying of Boxer’s hairdo, “God, what is that hair? So yesterday.” At the time Fiorina was recovering from cancer and growing her own hair back.

But Boxer had something Fiorina didn’t: a compelling narrative about her opponent.

Fiorina was, in Boxer’s telling, a monstrously greedy businesswoman who would rather fire American workers and give their jobs to China than take a pay cut, even though she made hundreds of millions of dollars and somehow found extra cash lying around for corporate jets and personal yachts. Worse for Fiorina, many of her public statements—that Americans are not entitled to jobs, for example—confirmed the story Boxer was selling.

When she first learned the details of Fiorina’s record, Boxer said, “I was shocked.” It wasn’t just that she had fired 30,000 people but the apparent callousness with which she had done so. They were, Boxer said, "summarily dismissed like some kind of garbage." Even now, so long after the Senate campaign, Boxer sounds like she still can't believe it. “That comes back to haunt you! You cannot do that. You cannot step on people when you're going up the ladder, because they don't forget.”

“The heartlessness,” Boxer sighed. “She makes Mitt Romney look like a populist.”

Boxer turned around to True, still leaning over the HP computer. “Is it ready? Come on,” she said, standing up and walking around the couch. “Let’s just take a look at this because I think it’s important. These are the people who actually got fired.”

The ad is called “Workers,” and it was released October 20, 2010. It begins with a bald, bearded man named Farrell. “I’m among 30,000 employees who used to work for HP,” he says. Another ex-employee—one of five in total in the video—chimes in to say the 30,000 employees were supposed to retire at HP. “Carly Fiorina changed all that,” Farrell says. Fiorina, they allege, shipped their jobs to China and India, and worst of all, “we even had to train our replacements.”

Boxer looked at me, her eyes wide, after the video ended. “It makes me cry,” she said.

The last time Boxer talked to Fiorina—after the initial, almost-forgettable meeting before she entered the political arena, and after their bare-knuckled debates—was the day after Boxer won the election. “She refused to make the phone call to congratulate me until the very next day. The next day!” she said. “I remember we were called by the networks immediately, and Senator [Dianne] Feinstein was with me, and she said, ‘Barbara, let’s go down and declare victory.’ And I said, you know, I don’t want to do that. Fiorina hasn’t called me. I always wait to get the call. And she said, ‘OK, 15 minutes.’” But the call didn’t come. “Fifteen minutes? No call. Half-hour? No call. And Dianne said, ‘I’m going down and declaring victory! If you don’t want to come, you don’t have to!’”

When Fiorina finally called, Boxer said, “I would not call it gracious. It was just, ‘It appears as if you’ve won.’ That’s what I remember. My memory of it was, ‘Well, it appears as if you’ve won,’ and I said, ‘Thanks for calling,’ and that was it.”

Then, Boxer said, amused, “She moved out of California! She left. She ran away.”