Joe Biden is working the phones with top donors while cloistered in his Delaware home. His digital team is searching for the right tone to ask small contributors for cash during the sharpest economic downturn in their lifetimes. And his finance operation is plotting how to keep the checks coming when catered parties for big contributors are on hold — indefinitely.

Top Biden fundraisers and donors, as well as campaign, super PAC and Democratic Party officials, described urgent efforts to reimagine the ways they raise money during a pandemic and global economic slowdown. And in nearly two dozen interviews, they expressed deepening concern that the downturn could choke off the flow of small online donations as millions of people lose their jobs.

The coronavirus shut down much of the American economy just as the former vice president took control of the Democratic presidential race, upending his plans to consolidate support among party donors who had previously supported other candidates and diminishing his ability to replenish his cash reserves to compete with President Donald Trump’s well-funded reelection campaign.

Trump and Biden face the same headwinds. But the president began March with an enormous financial advantage over the Democrats: a combined roughly $225 million in cash on hand between his reelection campaign, the Republican National Committee and their shared committees. Biden and the Democratic National Committee had only $20 million, after accounting for debts.

Biden’s campaign has not said how much money he has raised since mid-March, when the virus began taking its toll on the country, but multiple fundraisers said that giving was slowing and that they were reluctant to make aggressive requests for cash at this fragile moment, as the campaign itself readies for a 100% virtual and digital operation.

These should be some of the busiest and headiest days for Biden and his fundraising team in normal times, now that he has knocked out all of his rivals but Sen. Bernie Sanders, who trails by a nearly insurmountable 300 delegates. But instead he has found himself holed up in Wilmington, Delaware, and limited so far to three video fundraisers from a makeshift studio installed in the retrofitted rec room of his house.

“It is definitely harder to raise money now,” said Mathew Littman, a former Biden speechwriter in California who is organizing a video fundraiser and recently started a separate super PAC to raise money to support Biden in Western states. “The fun aspect of the fundraiser is taken out of it.”

“You have to be very sensitive to what’s going on with people’s lives,” Littman added. “This is definitely a much softer pitch than it was two weeks ago because the economy is going to be in either recession or a depression for a bit.”

Some top fundraisers said the notion of thumbing through call lists of friends to raise money for politics during an unprecedented economic and health crisis was tone deaf. Others are simply focused elsewhere right now. They are investors who have seen their portfolios hammered, business owners trying to triage their holdings and take care of their employees, philanthropists with links to cultural institutions at risk of collapse, or even health care systems bracing for the virus’s full impact.

“You don’t fundraise now,” Ed Rendell, a Democratic former governor of Pennsylvania and a Biden supporter, said in an interview a week ago. “I haven’t called anyone for money in the last 10 days and I don’t intend to. Not while people are confined to their homes. I just don’t think it’s appropriate. Plus, people are worried about money.”

While the Trump campaign begins with a big financial advantage, a suite of Democratic super PACs are helping the Biden cause, with more than $275 million in announced ads already.

Michèle Taylor, vice chair of a pro-Biden super PAC, Unite the Country, said the group was not proactively seeking out new donors right now given that “people don’t know what their economic future looks like.”

But money is still flowing.

“We’re still having donors coming to us, our fundraising continues to go well because people understand the urgency,” she said of getting rid of Trump. “We don’t have to tell people we need a change of leadership.”

Terry McAuliffe, the former Virginia governor and Democratic National Committee chairman, began meeting with donors on behalf of Unite the Country before the coronavirus froze such activities earlier in March. But after the primary ends, McAuliffe is expected to join the Biden campaign in some capacity, according to Democrats familiar with the planning.

The Biden campaign held one call in mid-March with an intimate group of some of the most prolific Democratic bundlers in the country, including Jonathan Gray, the president and chief operating officer of the private equity firm Blackstone; Jane Hartley, a former ambassador to France; Blair Effron, a founder of the investment firm Centerview Partners; Robert Altman, the founder of the investment firm Evercore; and Mark Gallogly, the founder of another investment company, Centerbridge Partners, according to people familiar with the call.

From his home, Biden has been making some calls personally, reaching out to those who initially supported other candidates while thanking early contributors and his most influential bundlers.

“In politics, we usually go back to the people who did the most,” said John Morgan, a Florida donor who hosted an event for Biden last year and spoke recently with him.

One person close to the Biden campaign said preliminary discussions were underway for how to plan for a situation in which in-person fundraisers do not happen all the way through the general election in November, though that is not seen as the likeliest outcome.

More and more of the campaign’s finance operation is going virtual. The Biden campaign also recently held a national finance committee call on which Jennifer O’Malley Dillon, Biden’s new campaign manager, was introduced.

Money has been relatively scarce for Biden throughout the 2020 race. Entering March, he was only the sixth biggest spender in the Democratic field, after running a relatively threadbare campaign during the primaries. All told, he has raised less than Trump had in the bank at the start of March.

“The press kept saying, ‘Biden has no money,’” Biden said at the last debate, on March 15. “And they were right. Biden had no money.”

But Biden struck it big with online donors after a South Carolina victory that propelled him down the path toward the nomination. He said at the same debate that he had raised $33 million in the first 15 days of March — far more than in any previous full month.

Then came the coronavirus, which has sapped overall online donations to Democrats on ActBlue, the party’s main portal for online giving. The site processed an average of $7.2 million per day of donations in the first half of March; that number has plunged to $3.7 million on average since March 16.

Biden does continue to spend heavily on Facebook fundraising ads — a sign that donors are still responding and giving, according to veteran digital operatives. Biden has invested more than $100,000 per day on Facebook since Super Tuesday, a level he had previously hit only in his first week as a candidate.

A number of top Biden contributors had hoped for a splashy in-person national finance committee meeting in April, seeing that as an opportunity to kick off the general election — but almost no one believes that such a gathering could occur in person now.

“If there are people who are waiting to contribute in association with an event, they need to get past that and go online and make a contribution,” said Howard Wolfson, a top strategist for former Mayor Michael Bloomberg of New York, who dropped out of the presidential race in March and has redirected $18 million to the DNC.

Multiple donors said they had been told that Greg Schultz, whom O’Malley Dillon replaced but who remains a top Biden campaign adviser, would be moved to the DNC, with a senior role coordinating between the party and the campaign, according to people familiar with the matter.

The campaign, which declined to comment for this article, has said publicly only that Schultz would be focused on “organizational planning for the general election” and “external outreach.”

Biden has not yet entered into a joint fundraising agreement with the DNC, which would allow him and the party to solicit far larger checks — for hundreds of thousands of dollars — compared with the current $5,600 limit.

The absence of such an accord is one of the more concrete effects of Sanders’ decision to stay in the race, hindering Biden’s and the party’s ability to close the fundraising gap with Trump. Biden almost certainly cannot formally clinch the nomination until June unless the Vermont senator exits sooner.

The DNC has said it would offer matching agreements in 2020 only to all “bona fide” candidates, after a backlash from the Sanders campaign to its 2016 agreement with Hillary Clinton.

Biden’s campaign had actually started experimenting with videoconference fundraisers months ago, after he was unable to attend an event in Baltimore because a tractor-trailer accident.

Biden held his first planned dial-in event in November and another in December. The benefits are significant: It takes far less time — often as little as 30 minutes. It does not involve any traditional hosting expenses. And there is zero time spent traveling from event to event.

“If used properly, you can still create a bond,” Michael Kempner, a public relations executive and top Democratic fundraiser who co-hosted two of the recent Biden virtual fundraisers. “You can still create deep personal interactions that feel as if you are in the room.”

As the campaign adjusts to the new reality, several pro-Democratic outside groups have been jockeying to serve as leading anti-Trump and pro-Biden entities in the coming months. On Monday, two of those groups, Unite the Country and American Bridge, announced a partnership.

There have been intensifying discussions among strategists and donors over which Democratic super PAC should lead the charge into November. Priorities USA, which was the biggest pro-Clinton super PAC in 2016, has already set a $150 million ad budget before the Democratic National Convention this summer, and the group announced a $17 million digital ad reservation Friday in a show of financial force.