(CNN)Joe Biden promises in nearly every speech he makes that "no one is going to work harder" to earn votes in the race for the 2020 Democratic presidential nomination.
'He's going to have to earn it': Can Joe Biden hold on to his place as Democratic front-runner?
So far, though, Biden has been less active than many of his competitors.
The former vice president has held 11 public events since launching his campaign on April 25. That's fewer than most other candidates: former Rep. Beto O'Rourke of Texas had held 12 by the end of his second night as a presidential candidate. Sen. Elizabeth Warren of Massachusetts held the same number -- four -- in Iowa on Sunday that Biden has held to date there. And Sen. Bernie Sanders of Vermont held three in New Hampshire on Monday, matching Biden's total for the entire campaign.
And unlike most of his opponents, Biden has usually declined to take questions from his crowds or reporters.
In addition to his public events, Biden has held nine fundraisers and a considerable number of private meetings with voters and strategists.
The sparse public schedule is likely to continue, with Biden likely to spend much of the next month fundraising and preparing for the first Democratic debate. The campaign's use of his time underscores Biden's decision to run a front-runner's campaign -- limiting his time on the campaign trail while seizing on opportunities to joust with President Donald Trump, but staying far away from the intra-party policy debates that could put him at risk of alienating segments of the Democratic electorate.
The Biden campaign, which expected a bump post-announcement, has to "figure out how to maintain momentum," a source close to the campaign said.
The campaign's thinking right now is "control the things you can control," the source said, by focusing on its plans while staying nimble.
His campaign appears to have chosen a strategy of having voters "see him less and remember him more," said Rebecca Katz, a progressive Democratic strategist who is not affiliated with a 2020 campaign.
"And that means remembering him as Barack Obama's vice president and the goodwill that comes from that -- and not necessarily Joe Biden the 2020 candidate, who is not as great a campaigner as some might remember."
In a statement, Biden's campaign pointed to the time he spends talking to attendees after his events and interviews with local reporters. It highlighted stops in each of the first four states to vote in the nominating process -- including one public event each in South Carolina and Nevada -- as well as speeches in Pittsburgh and Philadelphia.
"In the few weeks since announcing, Vice President Biden has stopped in all four early states and twice in Pennsylvania, talked to local media at each stop, done numerous gaggles with national press, and has never missed a conversation with a voter on countless rope lines and at events. Voters will know where Joe Biden stands on the issues, and his schedule will continue to be driven by engaging them in the most effective ways," Biden spokeswoman Remi Yamamoto said.
With the first month of his candidacy now in the rearview mirror, after an announcement tour that exceeded even some of his aides' highest hopes, Biden now faces an even bigger challenge: Can he maintain -- and build on -- his strength as the party's early front-runner?
The Democratic race is set to switch into a higher gear, with the first debates now just four weeks away. The schedule of multi-candidate events hosted by state party organizations, unions and other groups is ramping up, too -- and Biden's decision to reject invitations so far could create openings for audiences and the events' often influential organizers to drift to other candidates.
His campaign has also been slow to roll out detailed policy proposals. Two weeks ago, Biden told a crowd in New Hampshire that he would deliver "a major speech in detail" on his approach to climate change. With the end of May approaching, no such speech has been scheduled.
This week, Biden is poised to make some movement in the policy arena, with an education-focused trip to Texas. On Tuesday, he and his wife, Jill Biden, a community college professor, will appear in Houston at a town hall with American Federation of Teachers President Randi Weingarten before a fundraiser there. On Wednesday, Biden will be in Dallas; one source said an education-focused event will be held there, too, in addition to a fundraiser.
So far, fundraising has been a major focus of Biden's travels. He has held nine fundraisers to date, with more planned in the coming weeks in Boston, Atlanta and New York.
He has also spent time working while off the road. Biden was at his campaign's office in Washington for meetings last week.
Another priority in the coming weeks will likely be preparing for the first debate, scheduled for June 26 and 27. Veteran Democratic strategist Anita Dunn is leading Biden's debate prep efforts, with Ron Klain, his former chief of staff, also involved, a source familiar with the process said.
As most of his Democratic rivals fanned out across the campaign trail over Memorial Day weekend, Biden did not. His campaign perhaps unwittingly drew attention to that, sending out an advisory saying: "Joe Biden has no public events scheduled."
Biden and his wife will participate in Memorial Day events in Wilmington, Delaware, later this week.
J.D. Scholten, one of the most sought-after Democratic leaders in Iowa, said he believes the contest is wide open -- for Biden and his rivals -- as Memorial Day ends and the summer stretch of campaigning begins.
"He's a front-runner with quotation marks," Scholten said of the former vice president. "He's going to have to earn it."
In an interview on Monday, Scholten echoed the sentiment of several Iowa Democrats, who point out that Biden is months behind building an organization for the Iowa caucuses.
"His name is a bigger presence than his campaign right now," Scholten said. "They can't just bank off of people knowing him."
But for the next month, Biden will spend more time fundraising and preparing for the critical first debate than meeting early-state voters. His aides argue that he doesn't need to introduce himself like other Democratic hopefuls do, but they are mindful of the risks and know that early front-runners are often fleeting.
"He's not arrogant about this," a friend of Biden's said, speaking on condition of anonymity to discuss private conversations with the former vice president. "He knows he will have to fight for every vote."
Some Democrats said Biden has plenty of time to ramp up his schedule -- in part because as the front-runner, his every move commands attention.
"He can really drive the political speed limit and still take up the same room on the highway," said South Carolina Democratic strategist Antjuan Seawright. "He doesn't need to run political stop signs or red lights at this point."
Seawright pointed to shifts in the dynamics of the Democratic race since Biden's entrance. Candidates who had been rushing to prove their progressive bona fides have since paused, with Biden's more moderate approach proving popular so far. More shifts, Seawright said, could come after the first debate, depending on how it plays out.
"The worst thing he could do is respond to his opponents instead of responding to the electorate," Seawright said.
The rest of the field of Democratic candidates is watching Biden closely, with most taking a measured approach. While Sanders and Warren have repeatedly pointed out their policy differences with Biden, they have done so gingerly, mindful of Biden's broad popularity and the pitfalls of being seen as going negative.
When an Iowa voter asked Sanders last month about differences with Biden, he peppered those distinctions with kindness, repeatedly saying: "I like Joe."
"Needless to say, I hope I wi