Sen. Sam Nunn (D-Ga.) leaned forward on the hearing-room rostrum, his finger pressed to his temple, and bluntly questioned the witness about "incompetent management" of a federal program that cost billions of dollars.

Nunn was not talking about Pentagon procurement of weapons systems, a subject that gets much attention from the Senate Armed Services Committee chairman. At this hearing, Nunn was sitting as chairman of the permanent subcommittee on investigations of the Senate Governmental Affairs Committee.

And his subject was the Education Department's management of student loan programs.

"At this point in our investigation, we have yet to hear of even a single part of the student loan program that is working efficiently and effectively," Nunn charged in his opening statement yesterday. "The testimony has been so discouraging that one has to wonder if even immediate and concentrated reforms can, at this late date, salvage these programs."

When the first witness, a representative of consumer bankers, appeared to contradict Nunn's unflattering characterization of federal oversight of student loan programs, Nunn immediately challenged the testimony. William L. Banks, vice president of Chemical Bank, had called the programs "in the view of most lenders, overregulated."

Nunn asked how that could be when the subcommittee has "heard time after time, example after example, of underregulation." He noted that 11 employees in the California regional office are assigned to monitor 729 lenders in 14 states. "I have a hard time seeing how there could be overregulation with that few people . . . . The best they could do is fly over it, it seems to me," he said.

That tough tone has marked Nunn's five hearings so far assessing the problems behind student loan defaults, which the Bush administration estimates will total $2.3 billion this year. In addition to federal oversight, the hearings that began in February have focused on trade schools, accrediting agencies, lenders and loan guarantee agencies. The sessions continue today and next month.

Already, Nunn's attention to a perennial, costly problem has been noted within the Education Department, trade school industry and higher education establishment, the numerous associations headquartered at One Dupont Circle.

Issues raised in the hearings were the first and most discussed topic last week when higher education leaders held a back-to-school briefing for reporters. Two weeks ago, Education Secretary Lauro F. Cavazos announced new actions on 89 trade schools and seven accrediting agencies two days before Nunn heard testimony critical of them. A trade school organization made its leaders available for comment, even before a convicted trade school owner testified at that hearing about the ease of his fraudulent activities.

The impact could be lasting if Nunn and his hearings have any influence next year when congressional committees review student loan policies before Congress reauthorizes the programs for another five years.

A member of the House Education and Labor Committee, Rep. Marge Roukema (R-N.J.), has urged the House to hold similar hearings. She called for "quick action to rid the system of fraudulent {trade} schools and scam operators that bilk the taxpayers."

Others doubt that Nunn or Hill hearings will have much effect on student loan legislation. "I think there will be minimum {impact}. He's looking at the way things were," said Stephen J. Blair, a former department official who is president of the National Association of Trade and Technical Schools.

The NATTS Accrediting Commission was one of the seven that Cavazos cited. A department review found that more than 30 percent of loan defaults, a total of $365 million, was owed by borrowers who attended 89 trade schools. Those schools had been accredited by NATTS and six other agencies. The General Accounting Office made the same findings in its review for the subcommittee.

Referring to those schools, Blair said, "I can't justify a default rate of 50 percent and above."

Cavazos has ordered administrative reviews of those schools and has put pressure on the accrediting agencies to assure the quality of trade school programs.