OKLAHOMA CITY — At the age of 16, an “Okie” known to her friends as Liz Herring and to her family as “Betsy” graduated from Northwest Classon High School, her professional prospects limited by her gender and her politics fairly conservative.
On Sunday afternoon, she returned to the high school more than a half-century later as Senator Elizabeth Warren of Massachusetts, a left-wing candidate in the Democratic primary who has set out to shatter one of the highest glass ceilings imaginable: becoming the first woman to be elected president.
“I spent a lot of hours in this gymnasium,” Ms. Warren said. “I never thought I’d be down here, on the floor, doing something like this. But you know what — you don’t get what you don’t fight for.”
It was a personal and political homecoming at a key moment in Ms. Warren’s candidacy. Her monthslong rise in national polling has stalled in recent weeks. In response, Ms. Warren and her campaign team have made some marginal changes: a shorter stump speech in favor of more audience questions, and a greater willingness to have Ms. Warren criticize her Democratic rivals, particularly more centrist opponents such as the former New York City Mayor Michael R. Bloomberg, Mayor Pete Buttigieg of South Bend, Ind., and the race’s front-runner, former Vice President Joseph R. Biden Jr.
In Oklahoma, however, it was also clear what the campaign is not changing: It is holding close to her core progressive policies. Her aides are also hoping that as she continues to tell her personal story — one set in this state — Ms. Warren will beat back critics, including some Democratic rivals, who have sought to brand her as an ivory tower academic walled off from common citizens.
“Like a lot of Americans, I don’t have a straight path story,” Ms. Warren said Sunday, “my story has a lot of twists and turns.”
Ms. Warren highlighted parts of her biography that may be less known to the casual observer — her Oklahoma roots, working class background, and a family that includes several Republicans and military veterans. She pointed to her brothers in the audience and gave approximate distances to key places from her early life (the commuter college she attended was 45 minutes away).
She was introduced by her nephew, Mark Herring, who said Ms. Warren “worked her tail off for her family” even after she left the state. The campaign said about 2,200 people attended the event.
“She’ll always be Aunt Betsy to me,” Mr. Herring said. “And when she’s elected president, I’ll call her President Aunt Betsy.”
Fortunes can change quickly in a presidential primary, and for Ms. Warren to be the Democratic nominee in 2020, she will need to recapture the energy that surrounded her candidacy in the summer and early fall. By October, Ms. Warren had become the only candidate to best Mr. Biden in an average of national polls, and she was being hailed as the race’s ascendant front-runner.
But she has since fallen back, hurt by what seemed like an equivocating stance on “Medicare for all,” and voter fears that her policies would be too far left for the general election. Those same polling averages show her trailing Mr. Biden by more than 10 points, firmly in third place behind Senator Bernie Sanders of Vermont.
Sarah Neely, a 36-year-old teacher in Oklahoma City, said she noticed that Ms. Warren barely mentioned Medicare for-all in her Oklahoma speech. Ms. Neely, who backed Mr. Sanders in 2016 but is now supporting Ms. Warren, said she thought that was a good idea.
“The Medicare for all was a sticking point, especially around here,” she said. “But the more she’s out and speaking to people they can realize there’s more facets to the campaign than that. I’d tell her to focus on her anti-corruption message.”
Josh Elkins, 29, drove to the event from Tulsa, 100 miles away, even though his work shift began at midnight. Mr. Elkins, who also supported Mr. Sanders in 2016 and is now backing Ms. Warren, said Democrats need to get over the fear of nominating a progressive.
“Democrats stay home when they don’t nominate someone they’re excited about,” Mr. Elkins said, rattling off unsuccessful general candidates such as former Gov. Michael Dukakis of Massachusetts, former Senator John Kerry of Massachusetts and Hillary Clinton.
“Last time we nominated someone who was more moderate,” he said. “This time we need to have someone who invigorates progressives.”
The Oklahoma visit also reignited a more controversial portion of Ms. Warren’s past. Since the beginning of her political career in 2012, she has been dogged by her previous claims of Native American ancestry, criticism of which exploded last year after Ms. Warren took a DNA test in an attempt to verify the ancestry and quell the issue.
After significant backlash, including from within the Native American community, Ms. Warren apologized for taking the test — and for identifying as “American Indian” during earlier portions of her career.
She did not refer to the issue during her speech Sunday, even when a questioner asked what she planned to do for Native communities when elected president.
Ms. Warren responded by saying she wanted to create a cabinet-level position for tribal representation. She also promised to be a president who reset the country’s relationship with Native American leaders.
“We have failed at so many times to show respect,” Ms. Warren said. “And this is a time for us as a country to reset our relationship with tribal nations.”
Ms. Warren also met with about one dozen Native leaders for about an hour Sunday morning. She largely focused on her policy vision, according to people familiar with the meeting, which included discussion on improving Indian Health Service; upholding the government’s solemn trust and treaty obligations to Tribal Nations; improving education for Native children; and combating the opioid and substance abuse epidemic.
The campaign said that Ms. Warren had held several meetings with Native leaders this year, across several states. In a statement, Ms. Warren’s communications director, Kristen Orthman, said “Elizabeth was grateful to meet with tribal leaders this morning to discuss ways they can work together on many important issues facing Indian Country.”
Some tribes chose not to attend. In interviews, tribal leaders cited previous commitments, and some frustration that the national attention surrounding Ms. Warren’s ancestry claim has overshadowed more pressing local issues. A spokeswoman for the Cherokee Nation, one of the tribes Ms. Warren claimed to be descended from, said its principal chief was unable to attend because of a previous commitment.
The controversy over her heritage, a big discussion point in the months before Ms. Warren announced her campaign, has rarely come up among Democratic primary voters, but would certainly be a regular target in a face-off against President Trump, who has often referred to her with the derogatory nickname “Pocahontas.”
Much more important, especially in recent months, has been Ms. Warren’s ambitious progressive proposals, in particular her stance on health care.
Mr. Buttigieg has been a leading critic of Ms. Warren’s health care proposals. In last week’s Democratic debate in Los Angeles, Ms. Warren sought to hit back, seeking to brand Mr. Buttigieg as a candidate for the wealthy and well-connected after he held a high-dollar fund-raiser in a ritzy California wine cave.
Over the weekend, a published report showed that during her Senate campaign in 2018, Ms. Warren held a high dollar fund-raiser featuring expensive wine and a benefit concert from Melissa Etheridge. Asked by reporters if this constituted a contradiction, Ms. Warren said she has chosen to run her presidential race differently because of those previous experiences.
“I saw how this system works,” Ms. Warren told reporters. “And I decided when I got in the presidential race that I wanted to do better than that. And that’s why I just quit doing it. I don’t sell access to my time.”
Those are the kinds of sparring skills Ms. Warren honed at Northwest Classon. In a trophy cabinet outside the gymnasium, there was a debate trophy from 1965.
“Region I,” it read. “Class A. Liz Herring.”