Mr. Sanders on Tuesday came out in favor of “$2,000 cash payments to every person in America every month for the duration of the crisis.” And a group of Democratic senators — led by Mr. Bennet, Cory Booker of New Jersey and Sherrod Brown of Ohio — proposed sending as much as $4,500 to nearly every adult and child in installments this year.

In an interview, Mr. Khanna, a co-chair of Mr. Sanders’s presidential campaign, said he would be willing to work with those who wanted to send checks quickly, but was concerned that under some plans, financial help would not be targeted to those who need it most.

“This can’t just be a one-time thing,” he said. “It’s got to be more sustained, and when you’re sustaining it, it would become far better to give more dramatic relief to the working families and those who are unemployed.”

Indeed, the economic ripple effect of the virus is already being felt most acutely by service workers and hourly workers whose jobs have evaporated as Americans have been urged to practice “social distancing.” With so many Americans forced to stay home, some experts said that sending them money was the best way to stimulate the economy.

“We’re in a situation now where we’re almost surely going to have a recession. And unlike most recessions, we don’t want people going to work — we want a lot of people to stay at home and not be interacting socially,” said N. Gregory Mankiw, a professor of economics at Harvard and a former adviser to President George W. Bush. Direct payments, he said, would allow people to avoid putting their health at risk for a paycheck.

But Jason Furman, a Harvard economics professor who advised President Barack Obama, noted that while universal basic income had “a lot of attractive features,” it would be expensive to administer in the long run.

“Cash is very flexible and lets people make the choices that are best for them,” Professor Furman said. “But as a large-scale permanent program it would be very difficult to finance.”