Hillary Clinton was accompanied by Sen. Elizabeth Warren (D-Mass.) during a rally at the Cincinnati Museum Center at Union Terminal in Cincinnati on June 27, 2016. (Melina Mara/The Washington Post)

Sen. Elizabeth Warren disappointed liberals when she decided not to run for president. Many on the left were dismayed again when she didn’t make the cut as Hillary Clinton’s running mate, dashing dreams of an all-female ticket that could rev up the Democratic base.

But as she took the stage in prime time Monday night at the Democratic National Convention for perhaps the most anticipated speech of her career, Warren positioned herself to wield singular power over Democratic politics and the party’s policy agenda from her perch in the Senate, no matter who wins the presidency.

While Sen. Bernie Sanders built a mass following this year as a Democratic outsider demanding a political “revolution,” Warren has staked out her place as an agitating insider — pushing her party to the left on Wall Street regulation while lending her celebrity to raise money for the party and build useful personal relationships in the Capitol.

Warren signaled her intentions with a series of fiery attacks Monday night against Trump and GOP lawmakers. “This November the American people are coming for you,” she said of Republicans.

Warren, 67, has become a 21st-century political star, reminiscent of the late Sen. Edward M. Kennedy, the liberal lion who relished his role as political boogeyman to those on the right and hero to those on the left.

“She is a dominant Senate figure,” Boston Mayor Marty Walsh (D) said, noting that in a few years she has become the Bay State’s most popular Democrat among party activists. “There’s no question about it.”

More than Sanders, Warren has garnered the respect — and fear — of fellow lawmakers and Wall Street executives.

Banking lobbyists marvel, with consternation, at how Warren has developed a complex operation that hones what she does in the Senate with political outreach that only increases her clout inside the chamber and across the country.

One financial services representative, who spoke on the condition of anonymity to discuss the industry’s view of Warren, said that her brand identity as the enforcer of the Dodd-Frank financial overhaul has outstripped President Obama, who signed the law, almost creating an impression that Warren wrote the bill rather than simply serving as an adviser to the administration before her election to the Senate.

She is now, without question, the most feared Democrat on Wall Street issues, the industry official said, outpacing Sanders.

“She is the future, he is the past,” the industry representative said.

Warren’s biggest venue is usually a hearing room, where she goes for witnesses’ jugular. She often uses a five-minute grilling of a Wall Street titan — in which sometimes not a single question is really asked — and blasts it out within minutes through social media or her fundraising list.

At one such hearing, in 2015, the new chairman of the American Bankers Association, Dan Blanton, was on the receiving end. He was there trying to tout rules changes to benefit small community banks, but instead Warren turned her entire questioning into how that change would also benefit big banks such as Wells Fargo and JPMorgan Chase, leaving him flustered and unable to respond.

“Maybe you can get back to me,” she said.

Warren’s growing stardom on the left has made her more than her fair share of enemies, both among the banking industry and inside the Senate. Republican presidential nominee Donald Trump makes a point of ridiculing Warren by referring to the former Harvard Law professor as Pocahontas, because of a controversy during her 2012 Senate race in which it was revealed that her colleges counted her as a Native American professor based on questionable roots. Unlike many other Trump moments, no Senate Republican has criticized their nominee for his behavior toward Warren. Sen. Lindsey O. Graham (R-S.C.), an outspoken Trump critic, even called his Pocahontas tweets funny.

What remains to be seen is whether Warren can build on the political operation she has developed to become the sort of legislator who can enact laws and expand her legacy. That requires a skill set that Kennedy almost perfected in his bipartisan maneuvers but that, so far, Warren has not adopted.

Four years ago, when she addressed the Democratic National Convention in Charlotte, Warren was a mere candidate for office and was trailing Republican Scott Brown. Her candidacy only came about because Republicans, along with some Democrats, had refused to confirm her for the post she originally wanted, to head the newly created Consumer Financial Protection Bureau.

“I’m Elizabeth Warren, and this is my first Democratic convention. Never thought I’d run for Senate. And I sure never dreamed that I’d get to be the warm-up act for President Bill Clinton,” she told the delegates that night, nervously beginning her address.

She went on to defeat Brown that November and came to the Senate as a rising star, but one who was unsure of how to use her profile.

Warren has largely refused to deal with mainstream political media, breezing through the Capitol hallways without even pausing to decline comment to any reporter asking a question.

For the most part, Warren deals with liberal media such as the Huffington Post and MSNBC’s Rachel Maddow.

That has helped her become a liberal firebrand and a powerful figure who can upend her allies if they’re not careful.

Two prime examples were Obama’s consideration of Lawrence Summers to become chairman of the Federal Reserve and Antonio Weiss to be a top Treasury Department official. Warren joined forces with other liberals opposing both of those choices over their ties to Wall Street and rallied other Democrats to join her, leading to neither man getting confirmed to those posts.

In late 2014, Warren nearly provoked a government shutdown because she opposed a measure that was included in a spending bill that loosened a regulation on financial trades.

The provision wasn’t controversial at first, winning support from many Democrats.

But once Warren pounced, several dozen House Democrats backed off their previous support and, while the spending bill and its banking provision did become law, Warren sealed her place as the most important voice on banking issues.

The biggest distinguishing factor between Warren and Sanders, in terms of their power, is that Warren is playing the inside political game with all the tools at her disposal while Sanders, a self-described democratic socialist, is mostly sitting on the outside. He returns to the Senate, as well, but is likely to focus on rallying his supporters across the country to apply pressure on Washington.

Warren has raised millions of dollars for the Democratic Senatorial Campaign Committee and other candidates through email missives to liberal activists. Warren travels the country attending fundraisers and rallies for other candidates, as she did in late April for Rep. Tammy Duckworth (D-Ill.) in her bid to oust Sen. Mark Kirk (R-Ill.).

She has allowed more than two dozen emails to go out under her name, yielding millions of dollars in small contributions from her legions of fans.

That’s the sort of thing that earns goodwill inside the chummy Senate, where personal relationships can go a long way toward winning someone’s vote for the causes Warren is trumpeting.

Sanders, on the other hand, has only used his recently heightened profile to advocate for a few candidates who also backed his presidential campaign.

Warren has turned into one of her party’s best surrogates, delivering fiery speeches that bring the crowds to their feet, and her chemistry with Clinton at an Ohio rally seemed so dynamic that her consideration as running mate went from a real long shot to a real possibility.

Now that her future is likely to be in the Senate, Warren has to transfer this clout into wheeling and dealing that will advance her cause.