Just days after former Vice President Joseph R. Biden Jr. became the 20th candidate to join the Democratic presidential race, Senator Bernie Sanders of Vermont readied what he hoped would be his latest show of force: thousands of house parties across the country.
On Saturday, Mr. Sanders’s campaign kicked off its national organizing program with what it says are roughly 5,000 events across every state. Mr. Sanders addressed supporters via livestream.
The date for the organizing events was set weeks ago. But the timing is fortuitous. With Mr. Biden’s entry, the race has kicked into a new gear, and the organizing effort gives Mr. Sanders — who has been running second to Mr. Biden in most early polls — a fresh opportunity to lock up supporters and reassert his grass-roots strength.
The weekend also marks something of a turning point for Mr. Sanders’s campaign. For the first two months of his presidential run, he mostly held big rallies in early nominating states, including Iowa, New Hampshire, Nevada and South Carolina.
The rallies were intended, in part, to showcase the enthusiastic crowds he is capable of mustering, but also doubled as opportunities to sign up supporters. Now, with the field largely set, the events this weekend reflect the campaign’s next stage — turning the names on those lists into active volunteers.
“I’m not going to tell you that money is not important — we’re going to raise a great deal of money,” Mr. Sanders said in a phone interview on Friday afternoon. “But at the end of the day, I believe now — and I’ve always believed — that grass-roots activism is more important and more effective than 30-second television ads.”
He added, “When you’re running against 15 or 20 other candidates, I think the candidate who comes out on top will be that candidate which has a very strong and effective grass-roots movement.”
Mr. Sanders, perhaps more than any other candidate, is betting his campaign’s success on his grass-roots appeal. He hopes to have an army of volunteers spreading his message on the ground — knocking on doors, handing out leaflets, engaging on social media — to say nothing of the money his campaign hopes to continue raising through individual donations. He is also aiming to get volunteers involved in a “massive voter-registration drive,” focusing in particular on working-class and young people, he said.
There have been signs his strategy is working: In the first quarter, Mr. Sanders’s campaign raised more than $18 million, outpacing the other campaigns by far. On the campaign trail, he often boasts that his campaign has signed up more than one million supporters.
But as his campaign prepares to compete with Mr. Biden’s, those aims have taken on new urgency. On Friday, Mr. Biden’s campaign announced it had raised $6.3 million during its first 24 hours, besting Mr. Sanders, who raised $5.9 million in his campaign’s debut. (Mr. Sanders, however, raised his first-day total from some 225,000 donors, more than double the roughly 97,000 donors who gave to Mr. Biden’s campaign, which held a big fund-raiser on Thursday night.)
Mr. Biden has also planned a campaign stop next week in Pittsburgh — union country — underscoring that he is homing in on the same blue-collar voters who were drawn to Mr. Sanders in 2016.
In the interview, Mr. Sanders said he was aware he was unlikely to draw the same level of support — from working-class people and others — that he enjoyed in 2016, given there are so many other candidates, including Mr. Biden, in the race.
“It is absolutely true that not only Joe Biden, but every other candidate, is going to be going after the support that we have had in the past,” he said. But, he said, he still thought his campaign was well-positioned for the battle ahead.
“I think we are doing well in hanging on to the support of the folks that we had last time — not 100 percent, that’s for sure — and also reaching out and bringing new people in,” he said. “But you know? That’s what the fight is about.”