As Kirsten Gillibrand ascended to the pulpit at the Bridge Street AME Church in Bedford-Stuyvesant in late February, the congregation seemed to tense with apprehension. One of the oldest black institutions in Brooklyn, the church has played host to Frederick Douglass and Harriet Tubman; Congressman Hakeem Jeffries had just given a rousing speech, putting the current political moment into context by recalling how this community had survived slavery and Jim Crow (not to mention Nixon, Reagan, and George W. Bush). Now a diminutive white woman was stepping up to the microphone. Actually, to say that New York’s junior senator is white is to undersell whiteness. Kirsten Gillibrand, 50, is practically translucent.

She started off stilted, hesitant. The woman next to me looked on, thin-lipped and unimpressed. Then Gillibrand turned to the story of Esther, who, told that the Jews are about to face slaughter, realizes her responsibility to act. “Each elected leader,” Gillibrand said, her voice growing stronger, “has been placed in that position of authority for a time such as this … We are the ones who have to fight against the hateful words that come from the highest places, from the places of power in Washington.” With increasing volume and assuredness, she called on the congregation to “ ‘put on the full armor of God, so that on the day evil comes, today, you’ll be able to stand your ground’ … That is what we are called to do!” Gillibrand moved on to Philippians, shouting as the crowd rose to its feet, “We are the ones that God placed here at a time such as this to fight!” The woman next to me raised an eyebrow in surprised approval, and I recalled an anecdote from Gillibrand’s memoir that I had not previously believed, in which Al Sharpton referred to her as “Reverend Kirsten Gillibrand.”

The improbability of Gillibrand’s preaching skills matches the improbability of her role as a Democratic holy warrior against Donald Trump. Appointed to fill Hillary Clinton’s seat in 2009, Gillibrand came to the Senate with a reputation as a moderate upstate hack, an unremarkable product of New York’s political machine. Yet one month into the Trump administration, Gillibrand had staked out the most defiant position among her colleagues, casting the most “no” votes against his Cabinet nominees of any senator (although she did vote for Nikki Haley as ambassador to the U.N.), earning admiration from progressives frustrated by other Democrats’ initial willingness to “work with” Republicans. When Gillibrand spoke at the Battery Park rally against Trump’s Muslim travel ban in January, chants of “Kirsten 2020!” rang out among the protesters.

The heroic optics of her Cabinet resistance were partly accidental; after all, she could not have played the role of lone resister had any of her Senate peers read the Democratic mood better and refrained from voting for some of Trump’s more objectionable appointees. Even the most progressive of her fellow senators — Elizabeth Warren, Sherrod Brown, Bernie Sanders — got dinged for playing respectfully with the Trump administration. (Warren’s constituents were so furious after she voted for HUD Secretary Ben Carson that she was forced to explain herself on Facebook.)

Gillibrand’s Cabinet votes lined up with her principles: “I look at each nominee,” she told me. “If they suck, I vote against them. If they’re worthy, I vote for them.” But her positioning was also savvy. One of her strengths, sometimes mistaken for a hollow willingness to shape-shift, is her nose for where her constituents, and the country, are headed. Through some combination of happenstance and remarkable political instincts, she often manages to show up there early.

Photo: Milo Hess

When I first meet Gillibrand, it’s two and a half weeks after the inauguration, and she is rattled. “I have had so many anxiety dreams,” she says. “Constant anxiety dreams.” She describes waking in the middle of the night, fretting over a friend’s daughter who’d tried to sell her Girl Scout cookies: “Oh my God, I’ve got to fucking order those cookies. I’m terrible! I didn’t respond properly! So at three in the morning I’m typing out this email,” pretending to have a Girl Scout cookie emergency. “This little girl is doing what she’s supposed to be doing, learning how to ask for the raise, and I totally dissed it!” Gillibrand says, noting that she is now getting nine additional boxes of Samoas and Tagalogs and that, yes, she understands that it’s not really about the cookies.

In the weeks that followed the election, she says, Washington was eerily quiet. “Nobody was reaching out. Everybody was so crushed, like a sadness you couldn’t process,” she says. “Most of the people I know who were die-hard Hillary supporters, I didn’t talk to for at least two weeks. It was like a death in the family where you didn’t even want to call because it would be too hurtful.” When the Senate convened for its brief lame-duck session, it became clear that “a lot of people wanted to fight and a lot of people were still, in my opinion, shell-shocked, not sure what this new world was going to look like.”

Gillibrand explains the divide as generational, “the difference between someone seeing the election as it is and seeing the election as it would normally be.” One view is “he’s going to have his Cabinet; he’s entitled to his advisers; you don’t fight these kinds of things.” It depends, she says, on “how many administrations have you seen? How many times have you been around the block?” Some of those who have “lived a long time, seen it a hundred times,” believe the institutions will survive the challenges presented by Trump. “Then there are others that see it in terms of what I see: that it’s not going to be normal at all.”

Cohesive party strategy — at least among Democrats — in the Senate is not easily achieved. Minority Leader Chuck Schumer, says Gillibrand, “has a really hard job, to navigate each of these things on behalf of a caucus where 25 Democrats are up this cycle and ten of them are in moderate states.” Democrats were handed a gift in the form of the terrible Trump-Ryan health-care bill, against which they did present a united front. But it was not exactly a risk to take a stand against legislation so disastrous that a Republican-majority House wouldn’t vote for it. The question will be whether Democrats can keep it together for the next test: the confirmation vote on Trump’s Supreme Court nominee, Neil Gorsuch. Schumer has called for a filibuster, which Gillibrand of course supports: “I feel we have enough votes to defeat his nomination. But I do not put it past Leader McConnell to change the rules. What I don’t know is if Republicans will stand up to him or not.”

If they do, she believes, it will be because of pressure from their constituents. One of Gillibrand’s staffers describes her as “hair-on-fire excited” about the numbers of calls her colleagues are receiving from voters on any number of issues. “I’ve certainly never lived through an era like this,” Gillibrand says. “I’ve never lived through a moment in history where people are using their voices and becoming strong advocates for what they believe in.” The only comparable contemporary example is from the right: the tea-party wave that swept through Congress in 2010.

Nobody told women to march. Nobody told people to run to JFK after the immigration ban. The message isn’t coming from Washington.

“The grassroots are doing this,” says Gillibrand. “I mean, nobody told them to do it. Nobody told women to march. Nobody told people to run to JFK after the immigration ban. The message isn’t coming from Washington; that’s the crux. The message is coming from regular people, and no one is telling them what to do.”

“There’s victory in just seeing Democrats fight for what’s right,” says Ilyse Hogue, the president of NARAL, who often consults with Gillibrand on how to approach the caucus. “Kirsten understands that going along to get along yielded nothing in terms of compromise. I think she’s set a great model for the rest of the caucus.”

For someone who has established a position as one of the most anti-Trump Democrats in the Senate, Gillibrand seems to have a lot of Republican friends. She has avidly sought out conservative support for her most ambitious endeavors, including the 9/11 health bill and sexual-assault legislation, and has regularly partnered with Republicans on smaller-beans measures like banning microbeads from personal-care products, which she did in 2015 with Ohio Republican Rob Portman. “A remarkable success in an era of never doing anything,” she tells me drily.

Tennessee Republican Bob Corker once called Gillibrand a “honey badger.” One of her staffers says what this means is “she will work over her Republican colleagues hard to find a place they can agree.” (Dems, too: “Kirsten will follow somebody down the hall to talk to them about an issue, follow them into their office,” says Elizabeth Warren.) One of her favorite Republican partners, Susan Collins, whose wedding shower Gillibrand helped to throw five years ago, described her as “very tenacious, and I mean that as a great compliment.”

In early March, Collins and Gillibrand filed legislation to protect seniors against fraud, and Gillibrand hopes to persuade Collins to become a Republican co-sponsor of the Family Act, Gillibrand’s big paid-family-leave bill. “I know Susan’s worldview is similar to my worldview,” says Gillibrand. “Which is that we’re here to help people, and if we’re not helping people, we should go the fuck home.”

Gillibrand doesn’t limit herself to the more moderate Republicans. “We can work with anybody,” she tells me. “I mean, we passed the 9/11 health bill with Tom Cotton. Most people would assume I wouldn’t be able to work with Tom Cotton and Rand Paul and Ted Cruz.” Cruz and Paul joined Gillibrand (and Warren) in the fight for the Military Justice Improvement Act; she and Paul have proposed a bill to make child care more affordable via a tax deduction; and Cruz actually praised her as principled in his 2015 memoir.

But won’t becoming synonymous with resistance to Trump imperil Gillibrand’s bipartisan bonds? “Not at all,” she says, looking surprised by the question. “Most of these Republican senators did not think Trump was the best nominee. They don’t agree with everything he says.”

Collins predicts her Republican friends will stand by her: “She is a good person. And that still counts, even in the Senate.”

When Gillibrand arrived in the Senate in 2009, she had an A rating from the NRA. Her appointment was greeted by a front-page editorial in El Diario reading “ANTI-INMIGRANTE” and perplexed reactions from Democrats, who couldn’t imagine what then-governor David Paterson had been thinking when he selected this young upstate moderate to fill Clinton’s seat. (In 2013 he admitted to The New Yorker that one of the reasons he appointed her was that she was kind to him after he was cruelly mocked on Saturday Night Live.)

Gillibrand, née Rutnik and called Tina into young adulthood, attended Dartmouth, majored in East Asian studies, spent time studying in China where she roomed with actress Connie Britton, and interned for a family friend, Republican Alfonse D’Amato. “When I tried to join the Young Dems in college, it was all dudes, and I was not interested,” she says. “They were not nice to me, and I thought, Not my thing.” So far from any path to righteous politics was the young Rutnik that after getting her law degree from UCLA, she took a job at Davis Polk & Wardwell, where she defended tobacco giant Philip Morris.

But as a young lawyer, Gillibrand watched Hillary Clinton give her speech at the Beijing World Conference on Women — “Human rights are women’s rights, and women’s rights are human rights” — and suffered a serious case of FOMO. “I was pissed off that I wasn’t invited to that conference. ‘I’m a feminist and speak Chinese!’ I wasn’t there because I wasn’t involved in politics.”

It took her ten years, during which she joined the DNC’s Women’s Leadership Forum, worked on Clinton’s 2000 Senate campaign, served as special counsel to then–HUD Secretary Andrew Cuomo, and took another law job, before Gillibrand found the upstate House district in which she wanted to run … against a four-term incumbent for a seat that hadn’t been held by a Democrat in 30 years and where Republicans outnumbered Democrats almost two to one. Advisers told her it was a bad idea. But Gillibrand felt that changing upstate demographics and her opposition to the Iraq War could swing it her way. In 2006, Gillibrand was one of a handful of blue women to stage improbable wins in red districts, including Gabby Giffords, who also ran as a pro-gun Democrat.

But the gun-friendly, anti-immigration stances that Gillibrand espoused upstate became instantly toxic when she was appointed to fill Clinton’s Senate seat. Senior Assemblyman Peter Rivera released a statement calling her immigration positions, including her opposition to amnesty and support for a guest-worker program that he likened to “21st-century slavery,” as “border[ing] on xenophobia.”

“The press pool was taking bets on how many months I would last,” Gillibrand says. “There was nobody in the state who thought I had any shot at being a good senator.” She began a course correction immediately. Within weeks of her appointment, she was meeting with Representative Nydia Velázquez on immigration and visiting with the family of Nyasia Pryear-Yard, a Brooklyn teenager killed by a stray bullet at a party.

Gillibrand flinches the first couple times I bring up her flip — evidence to many that she is at least as opportunistic as she is idealistic, maybe more so. “I never changed my values,” she says defensively. Eventually she explains that her shift wasn’t an evolution; it was an education.

“You are literally meeting parents who’d lost their daughter, and I’m a young mother with babies and tons of hormones,” she recalls, crying even now at the memory. “I was so upset that I hadn’t heard their story. To know that I had not empathized with them, or not even understood the issue well enough to be a good advocate? I knew I was wrong. I knew I didn’t know enough. I was just embarrassed that I hadn’t taken the time to truly understand what that issue was about.”

During the 2016 primary, Gillibrand used her own change of heart to level criticism at Bernie Sanders, her frequent Senate ally, for his record on gun control, and suggested that Clinton, whom Gillibrand supported, hadn’t gone far enough on guns. It is frankly impossible to imagine either Clinton or Sanders putting the self-flagellating “I am embarrassed not to have known better” frame on their own past contortions. But Gillibrand tells a similar story about her shifts on immigration. “My district was 98 percent white,” she says. “I hadn’t sat down with people to know what it feels like to live with constant racism, to live with the constant threat of families being torn apart.”

“I was maybe a little bit tough with her,” says Velázquez, recalling how critical she had been when Gillibrand reached out. “She was moved, and quite emotional. I was surprised.” Still, she didn’t think Gillibrand would ever be an active senator on immigration issues. Velázquez pauses and laughs: “She proved me so wrong.” In February, Gillibrand brought a young Dreamer to President Trump’s first address to a joint session of Congress.

Gillibrand’s early years in the Senate happened to coincide with Democratic majorities, and she met with successes that buoyed her, including the repeal of “don’t ask, don’t tell” and the passage of the 9/11 health bill and the Stock Act, which prohibited members of Congress from trading based on insider information (a rule that Trump’s new Health and Human Services secretary, Tom Price, recently has been accused of violating).

“A lot of my early success was almost all luck,” says Gillibrand. “Yes, hard work and strategy and determination, but it was more than me just marching up a hill.” She also recalls Schumer’s mentorship in her early days, when he introduced her to then–party leader Harry Reid and helped her choose committees: She’s on Agriculture, Armed Services, and Environment and Public Works — which have offered her valuable distance from the sausage-making of financial-regulatory policy. As Jeff Hauser, head of the Revolving Door Project, points out, this means that she hasn’t been “forced to choose between influential deep-pocketed industries and the progressive wing,” which is important for a senator from New York who received more in donations from Goldman Sachs than any other Democratic incumbent for her 2012 race. (Gillibrand voted against the bank bailout while still in the House and has supported Dodd-Frank, though she has also been criticized by progressives for calling for simplification of the Volcker Rule and derivatives regulations.)

The Senate, Gillibrand says over lunch in Albany, “is not an easy place.” Her early wins have been followed by “year after year of fighting the same battles with no success,” she says. “Year after year of battles we haven’t been able to get focus on, not even a vote. We haven’t had a vote yet on sexual assault on college campuses. I was denied my vote last round on military sexual assault. And it gets frustrating.”

Gillibrand’s three-and-a-half-year fight to pass the Military Justice Improvement Act — which would remove prosecutorial authority from the military chain of command — has pitted her not just against generals but against some of her Democratic allies, including Claire McCaskill. “My faith has never been shaken,” Gillibrand tells me. “But my faith in the job has certainly been shaken. Like, I’ve gotten to the point where I’m wondering, Am I making a difference? Is this worth the time or effort?”

It’s enough to make a person turn to religion. “Bible study has really helped me,” she says. Raised Catholic, Gillibrand has for the past couple of years attended the weekly congressional prayer breakfast, plus two separate Bible-study classes with mostly Republican colleagues. “We visit together at Bible study and we talk about our families and things outside of the Senate,” says Joni Ernst, the Iowa Republican whose campaign ads touted her experience castrating pigs.

The biggest problem in Washington, Gillibrand tells me later, “is that not enough people have enough empathy. They can’t put themselves in someone else’s shoes. If they’ve lived an affluent life, they can’t imagine how expensive day care is. They don’t know why paid leave is important. They just don’t see it.”

This is partly why she wants more women to run for office. Gillibrand points to a moment seven years ago when the Stupak-Pitts Amendment — the brainchild of an anti-abortion Democrat that would have prevented women from using subsidized insurance to pay for abortions — threatened to derail health-care reform. It happened right before the 2010 midterms, when the percentage of women in Congress dropped. “I thought, What the hell is going on in this country?” Gillibrand says. So she launched Off the Sidelines, her PAC committed to electing more women. “That’s what I’ve been trying to do for five years,” she says. “Just telling women: If you don’t speak up, things aren’t gonna change. If you don’t become an advocate, it’s not gonna change. If you don’t vote, it’s not gonna change. If you don’t run, it’s not gonna change.”

The guys run every time. I can’t tell you how many 30-year-old dudes believe they should be senator or president.

Gillibrand is a bit of a gender essentialist. “Just literally having 51 percent of women in Congress representing the diversity of our country: You would have different issues raised, different solutions being offered, you’d have less partisan bickering,” she says. “Because our disposition is to help. When we do our legislation, we’re not trying to figure out how can I use this to run against you; we say, ‘How can we pass this bill to help both of our constituents?’ Our economy would be stronger, because we’d be dealing with things like paid leave and equal pay legitimately, as opposed to just using it as a talking point.”

When she first got to the Senate and started working on the 9/11 health bill (which her chief of staff had warned would be a tough sell — people thought New York was wealthy enough to pay for its own), she relied on the women around her for help. “To pass that bill, I first went to my female colleagues and said, ‘How do I do this? I have no fucking clue,’ ” she says. Her female Republican colleagues did not co-sponsor the bill, but they did give her advice: “ ‘Listen, if you pay for it this way and not that way, they can’t say no.’ ‘If you hold the vote, they’ll have to vote yes.’ They were whispering in my ear the whole time.”

Gillibrand, who was only the sixth sitting member of Congress to give birth while in office (her youngest, Henry, was born in 2008, the day after Gillibrand took a vote on the House farm bill), has been frank about her experiences as a woman in a male-dominated world, writing in her memoir about the older colleague who congratulated her on working out after giving birth because she was getting “porky.” Meanwhile, Harry Reid has referred to her as “the hottest member” of the Senate.

Hillary Clinton’s loss merely reaffirmed for her, she says, that “this is our landscape; we have to be successful in spite of the landscape. What voters need to see from a female candidate is different often from what they need to see from a male candidate. And, okay. Well …” She pauses. “It’s not okay, but it’s what it is.” She thinks Clinton’s campaign will get more women into electoral politics rather than scare them away. As evidence, she points to the Women’s March, which she describes as “the most inspiring moment of my life — because I believed five years ago that the women’s movement was dead.”

Through her fund-raising and Off the Sidelines PAC, Gillibrand has raised close to $6 million for women candidates in the past five years. “I will help you run,” she tells a young woman who says she’s thinking of entering politics at a recent event at the Manhattan women’s club, the Wing. “It doesn’t matter if you haven’t worked your way up. The guys run every time. I can’t tell you how many 30-year-old dudes believe they should be senator or president. Women, we’re like, ‘Well, maybe after ten years of working …’ No. Just run for the office you want to run for and run on the issue you want to fix.”

There’s plenty of speculation that Gillibrand will take her own advice and run for president in 2020. “It would not surprise me if Kirsten were a candidate for higher office some day,” says Collins. “She has enormous ability, she works extremely hard, she’s engaging, she’s young. And don’t take that as an endorsement, or I’ll be in even more trouble than I am now.”

Gillibrand, for her part, offers the standard politician’s denial: “I am running for the Senate in 2018.” But what is clear is that Gillibrand, who constantly carries a pad of paper with her, has been taking notes on the political moment. Though she supported Clinton over Sanders in 2016, she has much in common with the populist senator from Vermont. Like Sanders, she has often stood apart from Democrats. She “got an earful” for her vote against TARP, she says, and recalls her failed efforts to save $4 billion cut from SNAP benefits in the farm bill, which only 28 of her fellow Democrats supported, as “so heartbreaking.”

And like Sanders, she sees in left-wing populism — in affordable day care and paid leave and the expansion of Medicare as a means of addressing economic inequality — a path for red and blue America to come together. Sanders spoke alongside Gillibrand in March at a press conference in support of the Family Act, and Gillibrand is very enthusiastic about becoming a co-sponsor of Sanders’s forthcoming Medicare for All bill. “People want affordable health care,” she says. For the record, she’s not late to that party; Gillibrand supported Medicare for everyone when she ran in her House district in 2006. “It’s the solution, and it makes sense to people even in my two-to-one Republican district.”

Her fixation on populism and grassroots politics may be strategic, but the strategy does seem to dovetail with her ideals. After half a dozen conversations, when I ask her again about Democratic strategy going forward, she fixes me with a hard stare. “I am exceedingly sincere when I say this,” she says. “People only defeat Trumpism if everyone uses their voices on whatever platform they have available to them.”

She begins to tick through examples: the teen in Maine who wrote a letter to the Bangor Daily News and got Senator Angus King to write back to her on the issue of military sexual assault; the town halls that resulted in the eventual implosion of Obamacare repeal. “These things are real examples. I believe this. I truly believe it. It’s not bullshit,” she says.

Her main worry is that people will get tired — that eight weeks feels like eight years already, that this level of mass political engagement cannot be sustained. For that reason she tries to put this progressive fight into the context of battles past. “I’ve been doing a lot of study about the suffrage movement,” Gillibrand says, speaking to the women at the Wing. “Some of these ladies worked their whole lives and never got the right to vote. They literally worked a full 60 to 70 years.” She pauses, and I get the sense that she’s steeling herself as well. “So we can keep this up at least for two years, and then we can do it for another two.”

*This article appears in the April 3, 2017, issue of New York Magazine.