Almost entirely through the 2016 campaign, when Donald Trump would hold arena-style political rallies to crowds often in the tens of thousands, many political analysts repeated the same line: “Crowd size doesn’t matter, what matters is actual voters and scientific polls.”

Once, however, Donald Trump parlayed his raucous rallies into a political victory in November of 2016, there was a notable shift in the way that rally crowd sizes were taken into account. Certainly it’s impossible to extrapolate actual Election Day votes from an arena of 20,000 screaming and loyal fans, but there must be something meaningful about it when Hillary Clinton was typically unable to draw more than a few thousand even in the best of circumstances. She did manage to get a crowd of 18,500 in October of 2016 at Ohio State University, an event which was the largest of her campaign. Donald Trump was doing that almost weekly, at nearly any venue he chose.

Perhaps the main test of crowd size could be something akin to voter enthusiasm. Having motivated voters, willing to stand in line for hours on end for a two-hour rally could indicate a high degree of loyalty and a higher-than-average likelihood of voting on Election Day.

Fast-forward from 2016 to today and the same dynamic is being played out on the campaign trail. President Trump continues to hold large rallies, like the one days ago in New Mexico, and in some corners of the political world, the meaning of that crowd size is still being discounted.

One place where’s it’s not being discounted is by some of the President’s Democratic opponents. Sen. Elizabeth Warren, in particular, has been the one name, aside from Sen. Bernie Sanders, able to draw large crowds practically anywhere she goes around the country. Earlier this week, at a rally in New York City, Warren’s event drew some 20,000 people or more, and the political media took notice:

“Yeah, the lines keep getting longer,” Warren told reporters in New York on Tuesday, when asked about the four-hour wait for photos with her that capped her Monday rally, which was attended by more than 20,000 people. “That’s a good thing!”

Warren’s crowds show “that not only does she have broad reach – she has broad enthusiasm,” said Rebecca Katz, a liberal strategist who hasn’t endorsed a candidate in the presidential primary. To defeat Trump in the general election, she said, Democrats will need to nominate someone who generates the same excitement – pointing to the long line of Warren supporters who waited until nearly midnight for photos of her as one indication of her appeal.

“They were staying at her events for hours and hours after she finished,” Katz said. “There’s a lot of talk about raising money and electability, but there’s nothing nearly as important to winning in 2020 as voter enthusiasm.”

To Warren supporters, too, the overwhelming crowd size was meaningful.

“It’s so democratizing for a major presidential candidate to stand and wait for all the people who obviously want to see her,” gushed Devon Racinelli, 25, who was last in one of two lines that formed for photos with Warren on Monday night. The wait was so long that he had attended the rally, went to dinner and then returned for the picture.

The size of the crowd also inspired some to view a Warren candidacy as truly viable.

Electability may be key here. Donald Trump wasn’t viewed as “electable” by many Republicans in 2016, even if they mildly supported him. Then, the large rallies continued. The excitement of the rallies grew, and there is something about watching this kind of event unfold live on television that seems to overcome whatever flaws or questions some voters had about the candidate.

For Elizabeth Warren, it’s possible that for some Democratic voters, the same formula is helping her chart a course toward the being viewed as more electable.

Once again, this all boils down the electability argument. On paper, former vice president Joe Biden is “most electable” given his political pedigree and broad appeal. What he lacks, however, in a fashion similar to Hillary Clinton, is some kind of excitement attached to his candidacy.

It’s also noteworthy that other 2020 Democratic candidates have tried and been unable to put together many large rally events in the past few months, other than Warren:

Sen. Kamala Harris, D-Calif., attracted an estimated 20,000 people to Oakland for her campaign kickoff rally but nothing that big since then. Former vice president Joe Biden, who has the highest name recognition among the Democratic primary field, has so far favored smaller-scale events.

Harris did have very large campaign kickoff, and then it’s been all downhill from there. Warren, on the other hand, stumbled into the campaign with some badly produced web videos of her drinking a beer on New Year’s Eve in her kitchen. I think if you ask Warren she’s probably OK with how the campaign has developed up to this point despite earlier setbacks.

Bernie Sanders can’t be left out of this discussion about crowd size. Back on Sept. 10, Bernie managed a crowd of 10,000 in Colorado at a “birthday party” of sorts where the Senator from Vermont turned 78. So far, even back to 2016, Bernie has been the only Democrat to consistently draw larger-than-average crowds for his rallies. He’s not quite Trump territory with size and frequency, but his roadmap might be examined by his Democratic colleagues.

As one strategist put it, people watching Trump rallies may have originally tuned in to see the circus play out on their TV screen, but they ended up staying and eventually, some became ardent supporters:

“Trump would go have the greatest show in town, and it was hard to tell how many people were turning out because they supported him versus just coming for the free entertainment,” Conant said. “Everyone was late to appreciate the seriousness of his candidacy, but once he started winning places, it became apparent that people weren’t just turning out because he put on a great show, but there was real support there.”

The question is whether Elizabeth Warren or another candidate, like Bernie, perhaps, can muster the same type of excitement and enthusiasm to match President Trump’s rally crowd sizes and portray the same image of electability. Thousands of screaming fans helped give Trump a backdrop of support because many people saw his rallies and wanted to be a part of the next new exciting thing. In some ways, Trump’s success has been compared to Barack Obama’s in 2008. The newest face on the national scene, the most excitement among the party base, and the most enthusiasm to actually go and vote.

Trump is working to build off the 2016 success of his rallies and Democrats are still trying to figure out how much the rally sizes matter and how to combat them.

For what it’s worth, the Trump campaign scoffed at Warren’s crowd in Manhattan, noting the location should naturally be favorable for her, according to a spokesman:

He [Tim Murtaugh] added, “It’s no great feat for a leftist to attract people in Manhattan or Seattle and it probably took Warren’s campaign weeks of planning to do even that.”

This will be an ongoing battle throughout the campaign. If Warren can continue building momentum with rallies that draw large crowds outside of deep blue bastions like New York City, perhaps she’ll have found a winning formula to counteract Trump’s penchant for producing events ripe for TV coverage and designed to draw viewers into the President’s fold.