NINE OUT OF every 10 people who took out guaranteed student loans during their college years have paid them back. That might seem like a good percentage, but, in the loan business, a 10 percent loan default rate is disastrous. It works out to the uncollected sum of $4.1 billion.

The federal government is resorting to what it calls "the ultimate trump card." The U.S. Education Department, in an effort to recover that money, has asked the Internal Revenue Service to withhold income tax refunds for the approximately one million borrowers who have defaulted on their federal student loans -- unless they begin paying their debts.

Both the Education Department and the IRS say they are using the authority granted by the Deficit Reduction Act of 1984. The Health and Human Services Department already uses a similar program to withhold tax refunds from people who do not pay child support.

The student loan plan is welcomed by organizations such as the National Association of Student Financial Aid Administrators. Even the American Civil Liberties Union, that defender of individual freedoms, does not find fault in the idea. "People don't have the right to refuse to pay their debts," an ACLU spokesman said.

No one, including most debt-ridden college graduates, would argue that point. There is a question, however, of whether it should be the role of the IRS to act as a debt collector and turn its considerable powers of scrutiny on former college students or any other group of people. The IRS is charged with collecting taxes and that, as certainly evidenced by the delays in processing this year, is enough of a task.

The reasons for nonpayment of student loans are not always simple and clear-cut. Not everyone is a willful deadbeat. Some debtors are working, but not earning enough income to pay their loan debts now. Some less fortunate ones are unemployed. Others are being billed for courses they never took or did not complete. Some say they have in fact paid their loans.

The court system continues to be the best way to resolve these cases. Federal prosecutors also say that 50 percent of their cases are solved by agreeing on a payment schedule. A loan-assisted college graduate who has a job and refuses to pay off that loan must be compelled to pay, but the IRS should not be used as a debt-collection agency.