It was the night of Barbara Boxer’s greatest political victory. She had been re-elected to a third term as a senator from California, beating a credible challenger by a twenty-point margin and securing a higher raw vote total–6.9 million–than any federal candidate save George W. Bush and John Kerry. But Boxer’s party was in trouble. Democrats had failed to retake the White House and lost seats in Congress, and a decade after the GOP revolution of 1994 put both the House and Senate in Republican hands, the party that had for so long ruled Congress still did not seem to understand how to mount an effective opposition. “On election night,” Boxer recalls, “I said that I knew there were hard and tough times coming and that if I had to stand alone, I was going to do it. I’m not going to worry about what other people are doing. I’m going to be comfortable with being the only vote.”

To anyone unfamiliar with the continuing crisis of the contemporary Democratic Party–which, for the past decade, has been exacerbated by the supine character of its Congressional caucuses–Boxer’s statement might have sounded bizarre. Sure, things look bad for Democrats, but the party still has a substantial caucus in the Senate. So why would she be talking about standing alone? The answer is that Boxer, a liberal who shares the view of many grassroots Democrats that their party’s fortunes will be renewed only by showing strength, was implicitly acknowledging the reality that a lot of Congressional Democrats still don’t recognize: that Democrats have to become a genuine opposition party before they can ever again hope to become a majority party.

Barely two months after she made her go-it-alone pledge, the Senator would illustrate that point–perhaps unintentionally, but certainly effectively–when she lodged one of the most high-profile dissents in the history of the Senate. Inspired by electoral justice activists, who, she says, “definitely put the issue on the agenda for me,” and by conversations with Representative Stephanie Tubbs Jones, a Cleveland Democrat who was concerned about the disenfranchisement of minority voters in Ohio, Boxer objected to the certification of the presidential election results from that state. Boxer’s objection forced a two-hour debate that saw several Senate Democrats making pious statements about the need to count every vote, but she alone voted against certification.

Boxer’s move thrilled Democrats outside Washington–thirty bouquets arrived at her office afterward–but it did not meet with enthusiasm from her Democratic colleagues. Senate minority leader Harry Reid reportedly worried that Boxer’s move would paint Democrats as sore losers. Senator Mark Dayton, usually a reliable liberal, dismissed the challenge as “seriously misguided.” Press coverage focused more on the tear Boxer shed as she talked about disenfranchised minority voters than on the compelling evidence of the denial of democracy. White House spokesman Scott McClellan announced, “It is time to move forward and not engage in conspiracy theories or partisan politics of this nature.” But Boxer didn’t back off.

Less than two weeks later, she turned a Senate Foreign Relations Committee hearing on Condoleezza Rice’s nomination as Secretary of State into an unprecedented debate about the Administration’s manipulation of intelligence data regarding Iraq. Recalling Rice’s suggestion that Saddam Hussein might launch a nuclear weapon against America, resulting in a “mushroom cloud,” Boxer told Rice, “That image had to frighten every American into believing that Saddam Hussein was on the verge of annihilating them if he was not stopped. And I will be placing into the record a number of such statements you made which have not been consistent with the facts.” So tough–and on the mark–was Boxer’s attack that it inspired Saturday Night Live regular Amy Poehler to portray the chart-toting legislator confronting Rice with a bar graph contrasting a stubby line representing “the truth” with a long bold line for “what you say.” (Boxer loved it.)

And this time other Democrats paid attention to her objections. Senator Robert Byrd blocked Senate action on the nomination, upsetting White House plans to swear in Rice on Inauguration Day. That set up a heated debate on the nomination and the truthfulness of the Administration. Rice was confirmed, but a dozen senators, including Byrd, Edward Kennedy and Dick Durbin, the new minority whip, joined what has come to be known as the Boxer Rebellion.

Asked if she thinks that her questioning of Rice got fellow Democrats off their duffs, Boxer replies, “Absolutely.” Noting that Rice got thirteen No votes, she says, “That’s the most votes cast against a Secretary of State nominee since 1825.” She adds, “I think it’s a very powerful statement, even though to the outsider it doesn’t look like much. This is very unusual, and it sends a strong message to the Administration that we are going to be carefully watching their statements and their policies.”

Boxer got Republicans exercised. House majority leader Tom DeLay referred to the Senator indirectly as the spokesperson for the “X-Files wing” of the Democratic Party, while Fox’s Bill O’Reilly labeled her “a nut.” But grassroots Democrats were ecstatic to witness some fire from a Democrat in Washington. “Boxer for President” talk lit up the Internet, and when Boxer walked into parties and fundraising events around the country she was greeted with standing ovations. “More than anyone in the Senate right now, she is satisfying the hunger that so many grassroots activists feel to see someone stand up to this Administration,” says Ralph Neas, president of People for the American Way. And Boxer, to a far greater extent than most Democratic senators, relishes her relationship with the grassroots.

Perhaps it is because that’s where she comes from. While much is made of the students who got “Clean for Gene” when Minnesota Senator Eugene McCarthy waged an antiwar challenge to President Lyndon Johnson in the Democratic primaries of 1968, the backbone of the McCarthy campaign was actually young mothers. Boxer, who had recently moved from her native New York to the San Francisco Bay Area, was one of them. And like so many who got energized during that turbulent year, she remained in the fray–campaigning for a local antiwar referendum, building an influential environmental and antiwar group known as Marin Alternative, editing an alternative newspaper and winning a county board seat in 1976. Six years later, after her election to a Bay Area House seat, she arrived in Washington with all of her activist edge. It was Boxer who in 1984 earned national headlines and reforms in Defense Department procurement policies by revealing that the Air Force had spent $7,622 for a coffee pot. And it was Boxer who in 1991 marched House women to the Senate to demand a serious examination of sexual harassment charges against Supreme Court nominee Clarence Thomas.

The next year she was elected to the Senate. But at least in her first two terms, her edge seemed to be blunted. Even Boxer’s fans admit she was more a conventional liberal than a bold dissenter. San Francisco Bay Guardian executive editor Tim Redmond, who thinks Boxer worried too much about her 1998 and 2004 re-election prospects after a close race in 1992, sums up a common complaint about her caution on issues ranging from the Patriot Act, which she supported, to San Francisco Mayor Gavin Newsom’s gay-marriage initiative, which she criticized, when he says, “In her first two terms, she voted right, but she wasn’t the leader that everyone knew she could have been.”

Now that Boxer looks like a leader, there is a struggle to explain the shift. Predictably, there are suggestions that she has either decided to grab the spotlight in order to position herself for a presidential run or decided that, as this may well be her last term, she has nothing to lose. Boxer is dismissive of talk about running for President. “Not everybody in the Senate wants to be President,” she says. “A few of us like being senators.” The fact that she is an in-law of undeclared 2008 Democratic front-runner Hillary Clinton lends credibility to Boxer’s declaration–although if Clinton isn’t the nominee, watch for Boxer’s name on vice-presidential short lists. And, though she entertained the notion of standing down in 2004 before DeLay’s excesses caused her to reconsider, Boxer does not seem to be in a retiring mood.

Rather, the Boxer rebellion of 2005 appears to have less to do with the Senator’s own career than with her sense that Congressional Democrats need to reflect the grassroots passion she witnessed on the 2004 campaign trail. The woman who attended one of the first showings of Michael Moore’s Fahrenheit 9/11–she says it made her feel guilty for not objecting to the certification of the contested results from Florida’s 2000 presidential vote–and who posts thank-you notes to Internet blogs that have cheered on her recent dissents has been feeling more and more in tune with her party’s rabble-rousing base. “Look, I started out as an activist,” says Boxer. “And I came away from that knowing that activism is essential to any kind of change.” If people get disengaged because they don’t believe their representatives in Washington are listening, she says, “then bad things happen. And bad things are happening, to be honest. So we have to all wake up here.”

Whether Boxer can actually wake her party up remains to be seen. But as her profile rises, she is finding that at least some players in the party establishment recognize–as Republican leaders did long ago–that fighting the fights “the base” values can be politically smart. During the Rice nomination debate, the Democratic Senatorial Campaign Committee dispatched an e-mail appeal for contributions featuring a picture of Boxer and a letter from her that began, “The Republicans were expecting the Senate to confirm Dr. Rice with little debate and questioning from the Foreign Relations Committee. They didn’t count on me to ask the tough questions.”

Just as Republicans respond to the religious right, Boxer believes Democrats must pay attention to the legitimate fears and passions of those in the labor, environmental, civil rights and antiwar movements–even when this puts them outside the cozy relationships of official Washington, draws the fire of the White House and its amen corner in the media, and scares Democratic insiders, who often appear more afraid of their own party’s energized base than of empowered Republicans.

“I’ve won a lot of elections. And just about every time, the pundits said: ‘Barbara Boxer, she’s more liberal than her constituents. She’s never going to make it.'” Boxer says. “But I got elected. And this last time I got elected by a wide margin. So I think there is a message here–that people, even if they don’t agree with every single thing that you say or do, they do appreciate candor. They do appreciate someone who is going to say really what they think and not filter it through to the point where it’s mush.”

Barbara Boxer has taken the filter–and the gloves–off. Now, the question is whether she can get the Democratic Party to do the same.