Supporters of Ms. Warren’s plan said it would help people in jobs that require high levels of education but do not command top salaries, like teachers. Ms. Warren also presented the plan as a middle-class stimulus package that would put money back into the economy.

Paul Hankins, an English teacher in Sellersburg, Ind., said that in the next couple of years, his two children would be going to college, and everyone in his family would end up with student debt.

Mr. Hankins, 49, returned to school at 30 to become a teacher. He and his wife, a nurse practitioner, had taken on loans willingly to do what they loved, he said, and still owe almost $40,000 combined.

But “it’s a bill that we pay every month,” he said. “And the way you pay them, they hang on for so long. You’re like, ‘Wait, when was the last time that I actually sat in a classroom when I was doing this?’ I could put more money into my classroom if I weren’t putting money back into my education.”

Some critics questioned the value of such a huge investment in tuition and loan cancellation, and whether bailing out people with college degrees was the best way to spend nearly half the proceeds of Ms. Warren’s proposed wealth tax, which she estimates would bring in $2.75 trillion over 10 years. (Ms. Warren also proposes other uses for the increased tax revenue, like universal child care.)

“I think it’s a hard sell,” said Beth Akers, an economist and senior fellow at the Manhattan Institute, though she did give the Warren campaign credit for trying to make the plan progressive by tying it to income.

Others felt a one-time clearance of debt would not address the root causes of the nation’s student debt crisis. Matthew Chingos, director of the Center on Education Data and Policy at the Urban Institute, suggested that the plan was not forward-looking enough.