Sen. Elizabeth Warren was just getting started, when Eric, an apprentice electrician who works in the solar power industry, asked her how the country could move past an "antiquated system of energy."
To the crowd gathered at a community college gymnasium in New Hampshire last month, the Massachusetts Democrat responded by describing, in great detail, net metering.
Instead of just one factory creating energy, Warren explained, the idea is that "everybody's hooked up by wires," creating something called "distributive generation." The result: individual households, through solar panels on their rooftops or windmills, would produce and store their own energy.
"You do it while the sun shines, you store it up, and then you've got it 24 hours a day. Better storage at lower cost is going to help us overall," Warren continued.
She turned back to Eric in the audience: "Can I get an amen from an electrician on that?"
The room broke into applause.
Even before the official launch of her presidential campaign this month, Warren has made it clear that she is staking her candidacy on the belief that voters will be won over by her ease with policy and a limitless appetite for explaining how decisions in Washington directly affects their lives.
In her visits to Iowa, New Hampshire, South Carolina, Georgia, Nevada, California and Puerto Rico over the last seven weeks, Warren has fielded dozens of questions on an array of issues -- everything from net metering to the rising cost of homes to net neutrality to the Puerto Rican debt crisis. She has enthusiastically dived into the weeds, happily declaring herself a "nerd" who is proud to "wonk out."
She has already unveiled two major policy plans so far this year: last month, a "wealth tax" aimed at American households with net worths of $50 million or more; and on Tuesday, a sweeping universal child care proposal that would guarantee child care from birth until the time children enter school.
Warren's former students say her style on the campaign trail mirrors what they experienced in the classroom. Warren taught special needs children in the 1970s before becoming a law professor, teaching at numerous universities including the University of Texas in Austin, University of Pennsylvania and Harvard University.
Massachusetts Rep. Joe Kennedy III, who took a bankruptcy course with Warren at Harvard Law School, recalled that it was difficult to get a spot in her class.
"Her classes were known as the hardest classes at school, not necessarily because of the subject, but because of the teacher," Kennedy told CNN. "There's not usually a wait list to get into a bankruptcy class and there's very few people in this world that can make bankruptcy interesting, but she was one of those folks."
Kennedy, who met his wife in Warren's class, endorsed his former professor at her campaign launch event this month.
California Rep. Katie Porter, who also took Warren's bankruptcy class at Harvard Law School, said the way the senator lectured in the classroom is not so different from how she is now speaking to voters.
"This is someone who's spent her whole career explaining one of the most complex, arcane areas of law to law students," Porter said. "That's how she engages with voters. If she gives an answer and someone has a follow-up, she digs right in. If someone doesn't understand her point, she tries another way to explain it."
Michelle Wu, a member of the Boston City Council who was a student in Warren's contracts class in the fall of 2009, describes the senator as having been "beloved" on campus with "a knack for always being able to pick out who had not done their reading."
In the classroom, Warren often went deep into policy, Wu recalled, but there was always a broader goal of understanding how the existing system of laws affect "real people who would never have the chance to be writing the laws."
As more Democrats jump into the 2020 race, the next year will demonstrate whether Warren's unique approach can help her stand out in a crowded field.
She faces stiff competition from Senate colleagues like New Jersey's Cory Booker and California's Kamala Harris. Already, the stylistic contrasts are clear: Booker's announcement video, for example, featured a marching band; Warren's New Year's Eve message included line graphs tracking US income and wealth over the past few decades.
And while Warren has the potential to make history as the first female president, she has not overly emphasized her gender in the campaign so far. Booker and Harris both put their identities front and center in their campaign announcements, with Harris entering the race on Martin Luther King Jr. Day and Booker announcing on the first day of Black History Month.
The 2020 Democratic field grew by one more Tuesday morning, with Vermont Sen. Bernie Sanders also jumping in.
Democratic strategist Geoff Garin stressed the importance of simply being relatable -- particularly when voters have such a long list of candidates to choose from.
"I think there's a vibe from candidates that give people a sense of confidence. The vibe is sort of undefinable and indescribable. But you know it when you see it," said Garin, who is not advising a 2020 candidate. "And I think it's part of what sets candidates apart from another."
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