Since being formed two decades ago, the Education Department has had a hard time securing its place in the government firmament because of traditional local control of schools and serial conservative challenges to the department's very existence. The second secretary of education, Terrel H. Bell, entitled his memoir "The Thirteenth Man" because he felt left out of the Reagan Cabinet. Two other Republican secretaries, William J. Bennett and Lamar Alexander, later urged abolition of the department they had led.

But consecutive terms with a Democrat in the White House and education's rise as a prime political issue have put the department on firmer ground. Education Secretary Richard W. Riley has cruised to being the department's longest-serving chief, having been in office 6 1/2 years.

Riley has not made a media splash the way Bennett did--to focus attention on school issues and make himself the best-known education secretary to date. Instead, Riley has exhibited the same steadiness of purpose in coaxing improvements in the nation's schools as he did as a governor trying to boost South Carolina's educational performance.

"Anything in education that works well has to be the result of sustained activity," Riley said.

Riley's long run has kept many department officials around longer than usual. Now, with Clinton's second term winding down, some long-timers are drifting away.

David A. Longanecker, assistant secretary for postsecondary education, leaves this week to become executive director of the Western Interstate Commission on Higher Education, a cooperative of 15 western states based in Boulder, Colo. His six years in office stands as a record in what had been considered a burnout job: None of his predecessors lasted half as long.

"It took a while to convince career staff somebody cared enough about the place to stay a while," Longanecker recalled.

Longanecker arrived in 1993 with experience in Colorado and Minnesota managing college student aid programs, and he has left his mark on them in Washington.

Defaults on student loans have dropped from more than $3 billion in fiscal 1990 to about $1 billion in fiscal 1996 (the latest year for which figures are available), aided by a perking economy, more effective debt collection and an end to lending at 1,000 institutions, mostly trade schools, because of high default rates.

The department now directly makes about a third of the $12 billion in federal student loans, saving billions by cutting out middlemen.

Said to be in line to be nominated as Longanecker's successor is A. Lee Fritschler, the retiring president of Dickinson College in Carlisle, Pa. Two other department officials have headed in the opposite direction--back to campus as college presidents.

Jamienne S. Studley, who was general counsel, took over last week as the first female president of Skidmore College in Saratoga Springs, N.Y. Before coming to the Education Department in 1993, Studley taught law at Yale University and the University of California at Berkeley.

Next month, Charles Karelis takes charge of Colgate University in Hamilton, N.Y., after serving as director of the department's Fund for the Improvement of Postsecondary Education. The onetime philosophy professor was first appointed in 1985, when Bennett was secretary. "I have survived a lot of political change by keeping FIPSE below the political fray," Karelis said.

NOT ALL THE DEPARTURES from the department have been voluntary. After the White House did not renominate Pascal Forgione as commissioner of the National Center for Education Statistics, he resigned, effective June 21.

The White House decision surprised the former Delaware education commissioner, whose reappointment Riley had supported. Forgione has said the administration cited his long-standing failure to file income tax returns on time, even though it was not an issue during his 1995 confirmation hearing and he received a refund in each of the eight years he filed late.

White House concerns were said to have been raised after a Washington Post article last month noted that 9 percent of Education Department employees had either not paid all their taxes or had not filed returns, the highest rate in the government.

But Forgione's supporters have contended that his fate was sealed in February by his opposition to Vice President Gore's announcement of national reading test scores. Forgione sided with the independent board that administers the reading tests and has a rule against politicizing the results. Several GOP lawmakers have proposed legislation to mandate that only the commissioner can announce such test results.

Collecting national statistics had been the department's least controversial function, which dates back to the days of the subcabinet Office of Education.