The question is no small matter in a party still recovering from a bitter 2016 defeat — a loss marked by a lack of enthusiasm for an establishment nominee in several critical states.

Attendance at the former vice president’s launch rally paled next to some of his rivals. In his first Iowa visit, he didn’t match the crowds that greeted Elizabeth Warren or even the less well-known Pete Buttigieg in their initial visits. So far, he’s kept his events to smaller venues where there’s little danger of empty seats.

In the eyes of Biden’s progressive critics — as well as President Donald Trump, who has publicly mocked him for it — the seeming lack of excitement or teeming masses at his events is a leading indicator of a lack of passion for his candidacy.

“I started to think the polls were wrong about Biden because it’s not what we’re seeing on the ground,” said Aimee Allison, founder and president of She the People, a national network devoted to promoting women of color.

“Inspiration is the X-factor and we’re waiting for the inspiration from Biden,” she said. “When the inspiration isn’t there, the turnout from the core of the Democratic base — women of color — isn’t there. And then we lose.”

To Biden’s campaign, attendance figures are a meaningless metric. Focusing on crowd size is Trump’s game, it says, an emphasis on style over substance that attempts to turn audience engagement into an argument about the 76-year-old Biden’s energy level.

Crowd size, after all, is an imperfect metric to measure a campaign’s vitality. While it can be a revealing indicator, it still lacks the scientific underpinning of polling or the fixed-dollar figures associated with fundraising. Nor does it account forthe judgment of elected and influential Democrats across the country.

Just as critics doubted Biden’s popularity before he got in the race, his campaign is confident he’ll have the crowds when he needs them.

“We’re seeing enormous enthusiasm for Joe Biden’s candidacy across the country, beginning the very first day of the campaign when he got over 100,000 contributions — 65,000 of which were brand new to our lists — from all 50 states,” said Biden campaign spokesman T.J. Ducklo.

Even so, since announcing his candidacy more than a month ago, Biden has yet to draw anything near the 20,000 people who showed in Oakland to cheer on Kamala Harris when she announced, or the 13,000 who turned out in Brooklyn for Bernie Sanders’ launch.

Last Saturday, when Biden held a rally for his headquarters’ opening in Philadelphia, his campaign estimated the crowd size was 6,000 — a count thatsome local observers thought might be generous. One local elected Democrat who supports Biden privately told POLITICO the rally was smaller and less energetic than expected.

The event fell far short of the size his surrogates predicted in one of the nation’s largest Democratic cities. Just before Biden formally announced his candidacy last month, former Pennsylvania Gov. Ed Rendell, who helped organize a fundraiser for Biden, had loftier expectations.

“He’s enormously popular here,” Rendell, a former Philadelphia mayor, said in a late April interview. “We could get tens and tens of thousands of people … For one rally, I think we could do that.”

The crowd size was similar to what President Barack Obama drew at a 2016 rally for Hillary Clinton at the same venue. As a candidate, however, in April 2008, some 35,000 people flooded Independence Mall to see Obama — before he was the nominee.

Trump — for whom crowd size borders on obsession — seized on Biden’s Philadelphia launch, mocking the former vice president two days later at a rival Pennsylvania speech in which he exaggerated the smallness of the crowd.

“We have thousands of people … look at the thousands and thousands of people we have,” Trump said at a Montoursville rally, for which his campaign declined to release an estimated crowd count. “They said [Biden] had 600 people ... I’d say 150.”

It’s not the first time Trump has needled Biden over crowd sizes. In 2018, when the president and Biden held dueling Nevada rallies in the homestretch of the midterm campaign — and Trump’s Elko rally had more attendees than Biden’s Las Vegas rally — Trump used the occasion to point to Biden’s prior presidential race defeat and joked that Biden “was thrilled that’s one of the biggest crowds he’s ever had.”

It’s not just the size of Biden’s events that are modest,he’s also holding far fewer of them than his primary competitors. Since his launch, he’svisited Iowa only once. And while Democrats crisscrossed early presidential primary states during the long Memorial Day weekend, Biden took it off. (On Tuesday, he travels to Houston where he and his wife, Jill, will join an American Federation of Teachers town hall.)

There are signs that the theme could become more prominent as the campaign progresses. One of the president’s top surrogates, Florida Republican Rep. Matt Gaetz, said Biden won’t have the energy to campaign full time once he gets off “the French workweek campaign schedule” that the Democrat is currently on.

“He wants to make America bored again. It’s like he wants to put his audience to sleep,” Gaetz said.

“Trump’s rallies are big and raucous and enthusiastic. And the reason that matters is that in today’s politics, people want to be part of something,” Gaetz said. “Joe Biden’s rallies looks like an event where you would give a gold watch to the Democrat for a lifetime of service.”

James Carville, one of the masterminds behind Bill Clinton’s campaigns for president, said those criticisms miss an essential point about the kind of no-frills-no-thrills campaign he is running.

“He’s never been a candidate who has run on excitement. He has run on ‘you can trust me. I’m a good guy. My heart is in the right place. I’m human. You know me. I’m well-liked,’” Carville said. “Their theory of the case is people are tired of the circus. And it takes an experienced hand to settle everything down to get us back to some era of sanity.”

To that end, some Democrats say Biden’s sometimes listless crowds aren’t cause for concern, but merely reflective of the part of the electorate backing him: older, middle-of-the-road Democrats who are more likely to turn out to the polls than to boisterous megarallies.

Polk County Democratic Chair Sean Bagniewski said there weren’t lines around the block for Biden during his Iowa visit, but that at a local Democratic Party dinner, the former vice president’s campaign dominated local chatter.

“The polls are picking up the people who might not be going to the rallies, might not be going to the meetings. But the polls can still be right,” Bagniewski said. “The rank and file can be reliable Democrats. They’re the people who have been around for awhile.”

Brian Fallon, former spokesman for Hillary Clinton, said the Biden campaign isn’t going for big crowds and passion and is instead underpinned by “a very pragmatic argument. It’s not an argument designed to electrify. It revolves around electability ... It’s not the type of message that inspires a movement. It’s very practical.”

There’s also the matter of Biden’s long tenure in politics. Crowds that flooded to Buttigieg or Beto O’Rourke in this cycle did so in part because they’ve never seen the candidates before.

Tad Devine, who was part of Sanders’ insurgent 2016 campaign against Clinton, added that Biden doesn’t need the big crowds the way Sanders did in the previous race because the former vice president doesn’t need to show he’s a legitimate candidate — he’s the front-runner.

“Biden’s not a crowd candidate. He’s not Obama. He’s not Bernie,” Devine said. “Drawing big crowds is more important for Beto [O’Rourke] or Mayor Pete to get into the mix.”

Holly Otterbein, Daniel Lippman, Christopher Cadelago and Anita Kumar contributed to this report.