Proponents of the little-known state licensing laws say they are in taxpayers’ interest. Many student loans are backed by guarantees by the state or federal government, which foot the bills if borrowers default. Faced with losing their licenses, the reasoning goes, debtors will find the money.

But critics from both parties say the laws shove some borrowers off a financial cliff.

[An update: Two senators, Marco Rubio and Elizabeth Warren, plan to introduce legislation to prevent states from suspending licenses of student-loan borrowers who default.]

Tennessee is one of the most aggressive states at revoking licenses, the records show. From 2012 to 2017, officials reported more than 5,400 people to professional licensing agencies. Many — nobody knows how many — lost their licenses. Some, like Ms. Otto, lost their careers.

“It’s an attention-getter,” said Peter Abernathy, chief aid and compliance officer for the Tennessee Student Assistance Corporation, a state-run commission that is responsible for enforcing the law. “They made a promise to the federal government that they would repay these funds. This is the last resort to get them back into payment.”

In Louisiana, the nursing board notified 87 nurses last year that their student loans were in default and that their licenses would not be renewed until they became current on their payments.

Eighty-four paid their debts. The three who did not are now unable to work in the field, according to a report published by the nursing board.