ABC News(WASHINGTON) -- As the coronavirus crisis has devastated Americans across state lines and industry, it has also upended the 2020 election in numerous ways, including forcing the campaigns for President Donald Trump and presumptive Democratic nominee Joe Biden to walk a narrow line of continuing critical fundraising efforts while the country reels from an ongoing catastrophic health and economic hardships.

It's a line the Trump campaign sought to walk in its fundraising email to supporters on Monday.

"It’s no secret that our Nation was hit with a huge unforeseen challenge. We are in the midst of an all-out war with a dangerous invisible enemy,” reads the email, signed by President Donald Trump, which goes on to say: “While I’m fighting for the safety of our Nation and its citizens, I need to know that you are fighting for me too.”

The email then urges supporters to donate $35 to receive a "gold" Trump campaign membership card.

Due to the virus and state mandated bans on large gatherings, the Trump and Biden campaigns have been forced to put in-person fundraisers on hold.

The coming months of fundraising will be especially important for presumptive Democratic nominee former Vice President Joe Biden, who currently lags behind the president’s behemoth joint reelection effort between the Trump campaign and the Republican National Committee, which according to most recently available numbers has over $94 million in cash on hand. Biden has $12 million.

Biden has shifted to virtual fundraising efforts which include an upcoming “virtual fireside chat" digital event in April, which runs $2,800 a person for login instructions.

Trump Victory, President Trump’s joint re-election effort between his campaign and the Republican National Committee have also been holding virtual fundraisers, an RNC official tells ABC News, with more virtual events planned in the coming weeks.

And RNC chairwoman Ronna McDaniel, Co-Chairman Tommy Hicks, and Finance Chair Todd Rickets have continued to make calls to donors, according to the RNC official.

However, both campaigns have doubled down on raising small dollar donations digitally, which encompasses routinely asking voters to donate money through text messages, emails, and digital ads amid the global pandemic.

“Both campaigns have to tread carefully,” Joshua Sandman, professor of Legal Studies and Political Science at the University of New Haven tells ABC News. “They cannot be perceived as overtly partisan at a time of national crisis.”

“The candidates need to continue to reach out to their base and fund raise. However, their approach must be restrained, Sandman adds.

Ahead of last week's first quarter fundraising deadline, both campaigns bombarded supporters with donation requests. On Monday alone, the Trump campaign emailed supporters five times asking for donations, while Biden’s campaign sent four on Tuesday.

And while both teams have mostly steered away from directly mentioning the virus by name, their appeals for cash often invoke the country’s current dire situation in stark terms.

“These are uncertain times, and your health and safety is our top priority. But, we are also keeping a close eye on fundraising to ensure we have resources to take on Donald Trump this fall,” reads a text message the Biden campaign sent to supporters on Tuesday. “Would you chip in $15 to help us reach our goal?”

One Biden campaign fundraising email featured the subject line: “I hate asking you for your money right now…”

Another bluntly states, "It can be easy to forget it as the headlines each day are rightly focused on COVID-19, but the primary to select our Democratic nominee is still underway," before asking "Can you pitch in that $5 right now?"

President Trump's campaign invoked the coronavirus, without mentioning it by name, in a new fundraising email blasts this week, asking supporters to "fight" for him by donating to receive a "Trump Gold Card,” which is a membership card the campaign pitches to supporters in fundraising emails.

While the email doesn’t explicitly name the virus or mention the current pandemic, the fundraising email uses the term “invisible enemy,” which President Trump has used at press briefings.

In another fundraising email, Trump’s team acknowledged "our Nation is facing uncharted territory" while asking supporters to "please contribute $35 IMMEDIATELY" to receive a "PERSONALIZED Gold Card.”

A senior Trump campaign official defended continuing to fundraise during the pandemic, telling ABC News in a statement: “With five Democrat Super PACs hitting the President and dumping millions of dollars to spread misinformation, you better believe President Trump’s campaign will make sure we have every resource necessary to get him re-elected.”

The Biden campaign did not return ABC News’ request for comment.

Before suspending his campaign on Wednesday, Vermont Sen. Bernie Sanders had shifted their fundraising outreach efforts toward charity in responds to the coronavirus pandemic.

And while both the Trump and Biden campaigns have faced some criticism for continuing to fundraise amid the current crisis, other experts say it shouldn’t be all that surprising.

“Given the gravity of the choice of a president, it’s neither surprising, nor inappropriate, for the Trump and Biden campaigns to be raising funds in preparation for when the campaign begins again in earnest,” Bradlee Professor of government and the press at Harvard University’s Kennedy School of Government Thomas Patterson told ABC News.

Patterson said presidential candidates having to campaign amid wide-spread crisis is “not a break with precedent,” specifically referencing the 1864 election amid The Civil War.

“A number of presidential campaigns have been conducted in the midst of crises, 1864, 1932, 1944, and 2008 as examples,” Patterson said.

“The Civil War election of 1864 is the extreme example," Patterson added. "To a degree, the election was a referendum on Lincoln’s leadership of the Union war effort. One suspects that Trump’s leadership on the pandemic will figure at least partly into the outcome of this year’s election.”

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