Glenn Thrush is senior staff writer at Politico Magazine. Manu Raju is senior congressional reporter for Politico.

A sk Elizabeth Warren for her first impression of Hillary Clinton, and she doesn’t hesitate: She jolts forward to the edge of her seat, snaps her fingers and describes her as “quick!”

Clinton, of course, craves a more emphatic endorsement from Warren, hoping to bring the Democratic Party’s rising populist firebrand into her 2016 fold as soon as possible. Last year, she praised the Massachusetts senator as “a passionate champion for working people” at a campaign event they both attended; Warren was noticeably cooler and barely even acknowledged Clinton in her remarks. And, in December, Clinton invited a still-noncommittal Warren to her mansion in Washington. (Warren politely but firmly suggested that Clinton needs to take a much tougher line on Wall Street.)


But the Clinton encounter Warren remembers most vividly was their first, 17 years ago, when Clinton clearly had all the leverage.

Today, in her airy, high-ceilinged Senate office, Warren recalls being an obscure Harvard Law School professor summoned to deliver a command performance to Clinton backstage at a Boston hotel after the first lady had finished a speech. To this day, she isn’t sure Clinton quite knew who she was; East Wing policy staff simply wanted her to explain a GOP-sponsored bankruptcy bill, then get out. Clinton greeted her briskly, then tucked into a hamburger and fries as Warren launched into a passionate presentation against the bill: Tell the president to veto the damn thing, she said; it was a travesty designed to squeeze “the last couple-tenths of a percent” profit out of hard-pressed women and children who had fallen on tough times as a result of divorce, financial ruin or medical catastrophe.

“I mean this in the nicest possible way: She didn’t know this stuff. … But [she was] one of the smartest people I ever sat down with,” recalls Warren, remembering Clinton peppering her with questions between bites—and pushing the plate to the middle of the table to offer fries. “We get all the way to the end—and I still remember this ... she stood up and said, “‘We need to stop that awful bill!’”

Next came a first glimpse of the Hillary whirlwind: “She whips me outside of this tiny room … and she says, “‘PICTURE?’”—and here Warren impersonates Clinton by raising her voice to a crescendo—because the only possible answer was yes.

The first lady did, in fact, go back to persuade Bill Clinton to veto the bill, in Warren’s account: “The next thing that happens, there were skid marks in the hallways of the White House from advisers changing their positions after Mrs. Clinton got involved.”

But what happened later was even more telling—and set the stage for a complicated, tense and still-evolving relationship between the two strikingly dissimilar women atop the Democratic Party in 2015.

From Outside In A 2009 Daily Show appearance was one of Harvard law professor Elizabeth Warren’s early forays onto the national stage before her 2012 Senate election. In Congress, she has continued her advocacy for the middle class but, despite encouragement, insists she won’t challenge Hillary Clinton for the presidency. | Comedy Central; Michael Dwyer/AP; Andrew Harrer/Bloomberg via Getty Images

Three years after the hamburger summit, in 2001, Hillary Clinton, by then the junior senator from New York, had her own chance to weigh in on the bankruptcy bill. She voted in favor of a modified version (that provided limited protections for women and children) over the vehement objections of Warren and other consumer advocates. It passed, yet when Clinton was running for president in 2007 she glossed over that “yes” vote and claimed, during debates, that she “fought the banks” on bankruptcy reform. Warren has complained about it ever since, one of the reasons Bill Clinton refused to campaign for her during her 2012 Senate campaign. Another is Warren’s attacks on Clinton’s former Wall Street allies, a former Clinton aide tells us.

But Warren has a knack for getting the last laugh. She is now her party’s leading liberal alternative to Clinton, a role she clearly relishes. Despite her repeated denials she is considering the possibility of running, she remains a threat, and not just because her denials always seem phrased only in the present tense.

Warren speaks the language of populist grievance and scoffs at the Clintonian soft-pedal: She has told someone close to her that she remains “worried that Hillary and her people are still too damned close to Wall Street.” Sure, Clinton leads all potential Democratic challengers—Warren included—by 40 or 50 points, depending on the poll, but she lacks that kind of leftist brio. Plus, Clinton is rusty as a campaigner, addicted to six-figure personal appearance fees and a multimillionaire friend of Wall Street at a time of widespread concern about the country’s glaring economic inequality.

She would kill her credibility if she [ran],” Barney Frank says. “The second people perceive her as ambitious, you know, interested in running, that’s over.”

Some of Warren’s friends told us she would reconsider if Clinton were to exit the race unexpectedly. (“Opportunity knocks, and she runs towards it, obviously,” says Jody Freeman, a friend from Harvard, speaking more generally of Warren’s approach.) Run Warren Run, a group pressing her to run that is infused with $1.25 million from liberal groups MoveOn.org and Democracy for America, now has offices in New Hampshire and Iowa.

In an interview, Warren maintained, with a dismissive sweep of her hand before the question could even be posed, that the White House thing just isn’t going to happen. And she pushes back, hard, when we suggest that she is using her hard-won national platform merely to pull Clinton to the left in 2016. “You are framing it, in a sense, too narrowly,” she says. “No, the question for me is how can we change, how to make this country change, how to get this country back on a path where people can build real economic security.”

As for Warren’s own path? “She’s much, much too smart to run for president,” says her friend and ally, former Massachusetts Representative Barney Frank, who co-authored the Wall Street regulation bill passed after the 2008 financial crisis that included Warren’s signature initiative, a consumer board that looks after the interests of bank and credit-card customers. “She has no chance to win—none—and she would kill her credibility if she did. She’s devoted her life to issues that she cared about, and the second people perceive her as ambitious, you know, interested in running, that’s over.”

If she’s really not running for president, Warren, unlike Barack Obama or Clinton, has to figure out how to be a senator—a job she, somewhat improbably, enjoys. But can Warren actually execute the most challenging of Washington maneuvers, navigating the inside game without sacrificing the outsider principles? She certainly knows how to do it on a smaller stage: Warren has mastered the inside-outside game at every institution she has ever worked in, from Harvard Law School—where she rose to academic stardom by avoiding many of the ivory-tower campus fights that ensnared colleagues—to an inhospitable Treasury Department in Obama’s first term, where she set up her watchdog agency despite opposition from Obama advisers and Wall Street executives who to this day view her as the antichrist in a pageboy haircut.

But conquering the Senate, that marble-columned killing field of legislative ambition, has proved to be a far tougher task for Warren in her first two years. She has tried unsuccessfully to complete big deals on issues like student loan reform and housing. And her relationship with the White House, strained in recent years, has turned downright frosty thanks to her vow, transmitted to Obama and his top staff directly, to block the appointment of bankers to key posts. Here, too, as in her relationship with Clinton, Warren is trying to mix the inside with the outside games, hoping to “retain her purity without, you know, turning into Ted Cruz,” in the words of one senior Obama administration official.

But is it really possible to be both an ideologue, and a player, in today’s Washington?

“Sooner or later, you have to go produce something,” says West Virginia’s conservative Democratic Senator Joe Manchin, who tried and failed to get Warren’s support for a compromise deal that would cut interest rates on student loans. “You gotta say, ‘I did something.’ It’s one thing to just keep throwing the red meat out there and say, ‘Boy, I fed the lions today, they’re happy.’”

***

Many politicians come from humble beginnings. What makes Warren unique is how directly her academic and political careers have sprung from childhood setbacks and family anxieties.

In the 1960s, Warren’s father, Donald Herring, a salesman at a Montgomery Ward store in Oklahoma City, suffered a debilitating heart attack. Warren was 12 at the time, and over the next few years, the family flirted with financial collapse. Her father lost his new car, her mother took a job at Sears and Warren began busing tables in her aunt’s restaurant while in junior high. Even when Herring went back to work, they barely managed to scrape by as medical bills mounted. “It was a big damned deal,” she said.

Clinton, just two years older than Warren, has often talked about the constraints on ambitious women who came of age in the ’60s, but she was dating a future president in her early 20s, a time when Warren was struggling to escape the middle-American bouffant gulag. Warren dropped out of college at 19—abandoning a debating scholarship at George Washington University—to marry her high school sweetheart, had her first child at 21, worked awhile as a speech therapist, got a degree at a public law school in her late 20s, hung up a law office shingle outside her house at 30, divorced, remarried and launched a teaching career, all while raising two young kids.

Outsiders can say whatever they want,” Larry Summers counseled Warren, “but insiders don’t criticize other insiders.”

From the start, Warren yearned for a calling, not a career. She found one after snagging a job as a professor at the University of Houston in her early 30s—falling in with a group of law school and sociology professors studying personal bankruptcies. Conservatives have since challenged some of her results, but Warren’s team documented hundreds of cases in which hard-working families, like her own back in Oklahoma, were forced into bankruptcy by circumstances beyond their control, often the result of unexpected medical expenses. Villains lurked in those manila folders: the banks, the credit card companies and collection agencies.

And it turned out Warren had a flair that transcended academia, delving into the files for cases that would attract outside attention for her cause. Jay Westbrook, a University of Texas law professor who collaborated with Warren, recalls, “We found a debtor in Houston who had [agreed to pay] a debt for four new tires after the car had already been repossessed. That really caught [her] eye.”

By the late 1980s, her work was attracting national notice, and Warren moved to the University of Pennsylvania, where she rose quickly. Harvard Law came calling in 1995, and Warren jumped at the opportunity. She cultivated a tough but approachable classroom persona, while branching out into personal finance, which earned her an appearance on “Dr. Phil.” By the late 1990s, she had also become a go-to expert on an array of financial issues and was on the speed dial of congressional staffers. “She’s a lot smarter than most people think she is—and she hasn’t been a stranger to Washington,” says Dennis Kelleher, a former staffer for Ted Kennedy, the late Massachusetts senator who served as Warren’s mentor and legislative partner for a decade.

By 2008, Senate Democratic Leader Harry Reid needed a high-profile watchdog to head the congressional oversight committee monitoring the $700 billion bank bailout. He chose Warren, in part because she had the ailing Kennedy’s blessing.

It was her breakout moment: At a time when most of official Washington was arguing that scrutiny of the bailouts would destabilize the financial system, Warren pounded Bush Treasury Secretary Hank Paulson for details of how the big banks spent the $800 billion Congress had allocated; then, she hit Obama’s man at Treasury, Tim Geithner, just as hard. “I hammered Paulson. Then Obama picked Tim, and he adopted the same policies, so I hammered him too,” Warren told a friend recently.

If Kennedy was her patron on the inside, Jon Stewart was her angel on the outside, coaching her through stage fright during an appearance on his show in 2009 to explain the importance of holding the bailed-out banks accountable. In her 2014 memoir, Warren says she threw up repeatedly in a green room bathroom before taping, then stumbled on air, only to be saved by the sympathetic Daily Show host. Warren steadied herself, and was far more relaxed on subsequent appearances. By 2010, Stewart was kvelling. “I know your husband’s backstage, but I just want to make out with you,” he told her.

Using the platform Stewart provided, Warren pushed an idea she had first raised in a 2007 article: the creation of a consumer protection board, which she later argued should be inserted into the financial reform bill Democrats pushed after the financial crisis. It tapped the growing rage over the bailouts—and the Obama administration-approved bonuses to bailed-out firms—by proposing an agency that would investigate banking and credit card practices, payday lending and other financial activity prone to abusive practices.

Moreover, it appealed to Obama’s top political advisers, especially Valerie Jarrett and David Axelrod, who saw the political perils of the bailouts looming for the president in the 2012 reelection campaign.

Wall Street and the Republicans hated it—and Warren. But the board picked up an unexpected supporter in Warren’s longtime frenemy from Harvard, Larry Summers, who was by then Obama’s most influential economic policy adviser. Warren had long viewed Summers as an architect of deregulation and had criticized his role in eliminating the Glass-Steagall Act’s separation between vanilla commercial banking and risk-taking investment banking in the 1990s.

At a marathon dinner at the Bombay Club near the White House in April 2009, Summers and Warren argued over policy—but in the end he threw his support behind the board, which virtually ensured its creation. One exchange (recounted in Warren’s memoir) that stuck in Warren’s mind, however, was his advice—unheeded—on how to behave as a newly christened power player. “Outsiders can say whatever they want,” he counseled, “but insiders don’t criticize other insiders.”

***

The big financial reform package Obama had promised to pass when he was elected, Dodd-Frank, was enacted in the summer of 2010 with Warren’s new Consumer Financial Protection Bureau intact. Warren made no secret of her interest in running the agency. But opposition was growing among the cautious male advisers who made up Obama’s economic war cabinet. Summers, it turned out, didn’t want Warren to be an insider, after all. Geithner made the case to Obama that the Harvard bomb-thrower might destabilize the system, launching investigations just as many banks were returning to solvency.

Now Obama, in the words of Barney Frank, was “ambivalent” about whether to appoint Warren to head the agency she had pushed to create. He didn’t like her popping off in the Huffington Post all the time, and told Axelrod (who happened to live in the same D.C. apartment building as Warren) that she needed to “keep her mouth shut” about the appointment until he could work out the political details.

By this time, White House officials were feeling besieged by Warren and her lefty army: They were especially annoyed with a coalition of progressive groups’ petition calling for Warren’s appointment that garnered more than 350,000 signatures—in no small part because it was a stark reminder of how quickly she was coming to replace Obama as the darling of hard-core progressives.

Yet in the end, it was Republicans who killed her chances. Richard Shelby—the top Republican on the Senate Banking, Housing and Urban Affairs Committee—drafted a letter, signed by 43 colleagues, saying that the party would block any CFPB nominee over concerns with the agency’s mandate. “I felt like it would not be proper to make her the head of the consumer agency after she was the architect of it,” Shelby told us. “It looked like she was creating the job for herself.”

The Populist Professor After earning her law degree while she was a wife and mother of two young children, Warren taught law at the University of Houston, University of Texas, University of Pennsylvania and Harvard. | University of Texas School of Law; David L. Ryan/The Boston Globe via Getty; Suzanne Kreiter

Obama could have picked a fight and installed Warren as a recess appointment (as he did with the CFPB’s current head, Richard Cordray); instead, he offered her a chance to serve as interim director. At first she was disappointed—and demanded to know why the administration didn’t pressure top Senate Democrats like Chris Dodd to go to the wall for her nomination. But eventually, she accepted—and began raiding Geithner’s advisers for top talent, to the secretary’s annoyance.

By this time, the Boston Globe editorial page and her allies (and top Obama aide Pete Rouse) were talking up the possibility of Warren challenging GOP incumbent Scott Brown for the Senate seat once held by Kennedy. For a White House eager to see Warren make a graceful exit, here was an attractive proposition. At a congressional retreat, Obama approached Barney Frank on the photo line and asked, hopefully it seemed to Frank, “Do you think she’s really interested in the Senate?”

On the other side, Brown’s campaign team began second-guessing GOP senators for not just letting her serve on the board, where she would have posed no threat. Jim Barnett, Brown’s campaign manager, says, “I knew if they stifled this nomination, she comes back to Massachusetts and runs for the Senate, we’ve got a big problem on our hands.”

Warren’s eventual win was comfortable, if lackluster: She defeated Brown 53 percent to 47 percent in a state that delivered 61 percent of the vote to Obama. The race also exposed weaknesses aplenty, and many in the Democratic political class, eyeing her warily as a 2016 challenger, concluded she wasn’t quite ready for prime time. It was Warren’s first campaign, and she was an erratic and undisciplined candidate, too prone to shoot from the lip and thin-skinned when the media coverage turned on her.

She basically established that she has veto power over any nominee for the next two years,” says one former administration official.

The biggest blow, and one that still stings, came in the spring of 2012, when the Boston Herald reported that Harvard had touted Warren as a diversity hire (she identified herself as Native American), implying she claimed to be a minority for career gain. A stunned Warren stumbled for a week before her campaign rushed to the defense—producing testimonials from the school’s administration saying she had never sought to capitalize on the claim and circulating a Boston Globe story reporting that Warren’s great-great-great-grandmother listed herself as Native American in an 1894 document.

It didn’t seem like a rocket launch to the upper reaches of national politics. But for all her stumbles, Warren proved to be both a formidable fundraiser (West Coast liberals, not Wall Street progressives, were her base), and she monetized her YouTube popularity to the tune of $42.5 million, the most of any Senate candidate in that cycle.

She also had a talent for delivering impromptu broadsides on behalf of the middle class, in a visceral way Obama couldn’t muster. One off-the-cuff speech she delivered in Andover early in the campaign went viral. “You built a factory out there? Good for you,” she said, in a one-sided dialogue with a straw-man business owner griping about taxes.

“But I want to be clear: You moved your goods to market on the roads the rest of us paid for; you hired workers the rest of us paid to educate; you were safe in your factory because of police forces and fire forces that the rest of us paid for. You didn’t have to worry that marauding bands would come and seize everything at your factory, and hire someone to protect against this, because of the work the rest of us did.”

***

But the campaign left Warren chastened, and more overtly politician-like, sapping the spontaneity that made her such an appealing figure in the first place. Nowhere is that more apparent than on Capitol Hill, where she has hit the mute button around the Hill press, a strategic decision made for the purposes of self-preservation, brand-protection and focus. She doesn’t want to stand around spit-balling on topics—the Islamic State, Keystone, immigration—that diverge from her core economic message. “What I’m doing today is not different in intent from what I was doing 25 years ago,” she told us. “I’m on the same mission.”

But to John McCain, an old Senate bull who loves the back-and-forth, Warren’s attitude is small-ball, and ultimately self-defeating, because she won’t always be quite so in-demand. “That’s just foolish,” the Arizona senator and two-time presidential candidate told us.

Yet her diffidence is also a signifier of her status, and an Obama-like lack of neediness (she has little of the dive-for-the-microphone impulses of many colleagues). “She knows exactly what she’s doing and who she is,” says a fellow Democratic senator. “She doesn’t need to play the inside game, she’s got the outside game.”

Like Clinton and Obama, she stands conspicuously apart, a stiletto in a Senate full of thick-handled butter knives. If you blur the eyes it’s not hard to see a flicker of Hillary circa 2006: the blonde hair and pantsuits, the harried aides briefing on the fly, the head-snap reactions when she enters the room—the momentum of ascendant power whooshing by you to its uncertain destination. She is going somewhere, and fast. But where?

Her populist appeal permits her to campaign in red states Obama couldn’t set foot in, like Kentucky and West Virginia. She raised about $6 million for Democratic candidates in 2014—including some who weren’t in cycle, such as Washington Senator Patty Murray. This helped her within the caucus, particularly with Senate Minority Leader Harry Reid, who insiders say had been skeptical about Warren initially. He’s now one of her biggest boosters, in part because she’s one of the few Democrats who can rile up voters on the campaign trail.

The sly, strategizing Reid recognizes she’s the party’s future and has brought her ever deeper into the fold. In November, after he had lost the Senate, a rump group of Democratic moderates openly talked about his ouster. Reid, recognizing his sudden vulnerability, immediately struck on the idea of giving Warren a seat at his table.

Reid first proposed the idea to New York’s Chuck Schumer, his de facto Senate No. 2 who represents Wall Street; Schumer had a friendly relationship with Warren, but he questioned how elevating the freshman would be perceived inside the caucus and proposed bringing in the centrist Mark Warner, an ally from Virginia, onto the leadership team to balance out Warren’s liberal politics. It didn’t go over well. In a meeting, Schumer told her he wanted her to be a “liaison” to liberal groups. She scoffed at it—and later told the Huffington Post, “I don’t quite understand it.” (People close to Schumer say there wasn’t any friction.)

Schumer ultimately agreed to give her a role of her choosing as a policy and messaging adviser.

***

Warren has often said her beau idéal in running for Senate was the man whose seat she now occupies, Ted Kennedy, known for his long-arc view of legislating (his signature cause, health reform, passed seven months after his death) and willingness to partner with Republicans on big compromises.

The current Senate is far less hospitable for deal-making than it was during Kennedy’s day, but two years in, Warren has struggled to balance her principles with her desire to get things done. Despite her outsized influence, she hasn’t yet chosen to stake reputation on compromise.

Her biggest chance came in 2013, when she took the lead in the Democrats’ effort to deal with ballooning student loan debt, an issue at the heart of the party’s economic reform agenda. Democratic Senators Dick Durbin of Illinois and Joe Manchin of West Virginia were part of a bipartisan group of senators looking to cut a deal aimed at lowering loan rates that had pushed overall student debt to more than $1.2 trillion. But Warren believed the compromise rate didn’t go low enough for students and pushed back, introducing a bill that tied the reduction to a tax on millionaires—a poison pill that ensured GOP opposition. Her bill had Obama’s support, and Senate Democrats lined up behind it. But it fell two votes short of the 60 needed to break the Republican filibuster in the then-Democratic-controlled Senate.

“We’re gonna have to keep hitting at this,” Warren told Politico in September—but the GOP takeover of the Senate two months later put the bill in the deep freeze.

As one senator who has worked closely with Warren puts it: “She’s an academic. Academics have difficulties sometimes pulling the trigger on things. And everything has to be just perfect. And the world we live in, I’m sorry, that’s just not the way things are.”

Durbin, a liberal Warren ally who is habitually loath to criticize fellow Democrats, gently suggested that Warren’s perfect might have been the enemy of the greater good in the loan deal. “What I was trying to do was to figure out what was possible,” Durbin told us. “I think what we achieved was certainly better for the students—not as good as Senator Warren’s position—but I think reflected the political reality.”

Around the same time, Warren’s opposition helped doom a more controversial bipartisan deal on low-income housing being pushed by then-Obama Housing and Urban Development Secretary Shaun Donovan, a move that embittered administration officials who were angry that she didn’t come up with a workable alternative.

But she’s clearly looking for dance partners in both parties, and has charmed many Republicans who opposed her nomination to the CFPB, kibitzing in the cloakroom and sending handwritten thank-you notes after meetings. (Ninety percent charm, 10 percent confrontation is how one ally described her political formula.) Warren has also buttonholed another GOP committee chairman—this one an old friend of Ted Kennedy’s. She met with Orrin Hatch, the Utah Republican, to draft a bill dramatically ramping up spending on biomedical health research.

Hatch praises Warren as “charming,” but when he talked about Kennedy, he noted how the two were fierce liberals—with a key difference. “He would move to the center,” Hatch says of Kennedy, who was one of his closest friends and with whom he worked to pass the Children’s Health Insurance Program back in 1997. “I’m not sure that she’s learned that yet.”

***

So far, Warren has hardly been hampered by her ideology—to the contrary, it’s the source of her power and her main lever in moving the Senate, Obama and ultimately Clinton.

No Democrat is better at choreographing her inside moves with outside players. In her concert with liberal advocacy groups and unions, she has collaborated for years on financial regulation and bank oversight—especially with the AFL-CIO, MoveOn.Org, the Campaign for America’s Future, the Progressive Change Campaign Committee, Better Markets and a handful of others. Warren is particularly close to AFL-CIO President Richard Trumka and Damon Silvers, a senior union official who is one of Warren’s closest friends.

Warren also sees her role as an early warning system, alerting her caucus—sometimes to its annoyance—when it is diverging from its base. Early this year, Senate Democrats debated whether to give Republicans a relatively easy win on the Keystone XL pipeline bill—or whether to fight them. Warren joined calls to drag out the process, and Democrats did.

She is acutely concerned about being compared with Ted Cruz, the Texas Tea Party firebrand who has alienated many Republicans by repeatedly bucking his own leadership—and she embraced her role in the party pecking order, in part, to prove she’s a team player.

But she has no such qualms about challenging the president and will never forget he was unwilling to bear the slings and arrows of her CFPB confirmation battle on her behalf—a declaration of political independence not lost on the wary Clinton crowd.

Warren spearheaded the behind-the-scenes campaign to deny her old nemesis and fellow Harvard superstar Larry Summers the chairmanship of the Federal Reserve, a position the gruff economist viewed as a career capstone. When rumors of Summers’ imminent appointment first surfaced, Warren—who had squared off against Summers on virtually every issue from the ’90s bankruptcy bill to banker bonuses—told friends she would do everything in her power to stop it and worked with allies to kill the appointment before it was officially announced.

Obama wanted to appoint Summers, but Warren, several people told us, made it clear to Obama, using ally Valerie Jarrett as a conduit, that she was backing the more progressive Janet Yellen for the post. But she was also mindful of a possible backlash if she were perceived as engineering the attacks on Summers—and let other anti-Summers Democrats like Oregon’s Jeff Merkley, Ohio’s Sherrod Brown and Montana’s Jon Tester grab the spotlight in the days before the White House announced that Yellen, and not Summers, would be nominated.

When we asked her about the Summers fight, Warren smiled knowingly, and described her iron-fist, velvet-glove approach to confronting power.

“You can’t back somebody else into a corner,” she told us. “Someone has to make their own decision. You have to give them plenty of room to do that.”

But many administration officials (Obama isn’t one of them, according to several people in his orbit) resented what they viewed as a power play geared at increasing her street cred with progressives. “There’s a loyalty question with Liz,” a top adviser to Obama told us.

There’s a loyalty question with Liz,” a top adviser to Obama told us.

That concern was cemented when Warren led the effort to quash Treasury Secretary Jack Lew’s choice for the third-ranking official at the department, Antonio Weiss; she viewed Weiss, a former Lazard investment banker, as too cozy with Wall Street—and had informed Lew personally that she would oppose any similar nominee. (“No one should have been surprised. They knew! They knew! They knew!” she told us.) “It was a huge win for her,” says a former Treasury official. “She basically established that she has veto power over any nominee for the next two years.”

But she has had less success at her core legislative mission—protecting Dodd-Frank and other regulatory measures from being undermined by the big new GOP majority. In December, Warren opposed a bipartisan omnibus bill during the lame-duck session—a backroom deal hatched by Republicans, Reid and Obama—over language aimed at weakening oversight of derivatives trading.

Warren was incensed, and allied herself with House Democratic leader Nancy Pelosi to whip her liberals against the measure, but she lost after senior Obama administration officials led by chief of staff Denis McDonough twisted arms. Moreover, her opposition angered fellow Senate liberal Barbara Mikulski of Maryland, then chair of the Appropriations Committee, who had agreed to the derivatives compromise, in part, to shield Warren’s beloved Dodd-Frank from being further gutted.

Warren addresses a Capitol Hill rally in support of Social Security and Medicare in September 2014. | Chip Somodevilla/Getty Images

Warren delivered a blistering floor speech: “There is a lot of talk coming from Citigroup about how Dodd-Frank isn’t perfect. So let me say this to anyone who is listening at Citi—I agree with you. Dodd-Frank isn’t perfect. It should have broken you into pieces.”

This was a stark demonstration of the limits of Warren’s influence. But around the same time, Hillary Clinton—whose staff is deeply concerned about the threat posed by Warren—was proving just how important the constituency Warren speaks for is to the party’s future. She must be kept inside—if only to stop her from going outside.

In December, the former secretary of state invited Warren to her mansion on Whitehaven Street in Washington, ostensibly part of a series of consultations on policy ahead of a spring campaign kickoff. The meeting was civil (tea this time, not burgers), but Warren approached the encounter gingerly, with none of the naive expectations of her first meeting with Clinton in 1998. She has never forgotten or forgiven Clinton’s switch on the bankruptcy bill—and her skepticism has only been stoked by Bill Clinton’s aggressive recruitment of Wall Street donors for his foundation. Warren is also concerned about the former president’s close relationship with a cadre of pro-bank advisers he has consulted for two decades, chief among them Summers and former Treasury Secretary Robert Rubin.

At the meeting—it was one on one, no staff, like the first—Clinton didn’t ask for Warren’s endorsement, which was just as well, because she wasn’t prepared to give it yet.

Instead, they discussed policy, including the student loan bill and middle-class messaging. Eventually Warren, who had an agenda of her own, got to the heart of the matter.

According to two people briefed on the interaction, she prodded Clinton to pay special attention to whom she hired. Then came a look-Hillary-in-the-eye moment, one person said. Warren suggested that the probable Democratic frontrunner do more to distance herself from the titans of finance and advised her to stock the White House economic team and Treasury Department with fewer big-bank Wall Street types and more outsiders, independent outsiders—like, say, Elizabeth Warren.