As U.S. Secretary of Education William J. Bennett prepares to step down in a few days, he is leaving behind a mixed legacy.

It is a legacy of demands for educational excellence minglged with controversy. In the process, he has sharpened the national debate about education in ways that few others have done.Bennett, who succeeded Utahn T.H. Bell as education secretary, has been a combative, controversial figure from the first. His 31/2-year tenure has been marked by repeated conflict with teachers and higher education - the very people for whom his office is supposed to provide leadership.

There is nothing basically wrong with that. Some blunt comment from time to time is good for the education establishment. Unfortunately, Bennett seemed to be in an adversarial position nearly all of the time.

He has been an advocate of cuts in federal aid to education, an outspoken critic of teacher unions, been caustic about the "greed" of higher education and rapidly-rising tuition costs, and critical of what he calls spoiled college students.

Despite the criticisms, Bennett also has had a solid message.

He champions what he describes as the "three C's" of education: choice, character, and content. He bitterly argues against routine, against stifling administration, and in favor of rewarding skilled teachers. He declares constantly that teachers have a duty to impart strong morals to their students. He solidly backs local control of public schools. And he proposes higher, tougher, unyielding academic standards for all schools. Only a few days ago he called for even the elementary schools to put more emphasis on literature, foreign languages, history, and civics.

These are worthy goals that need more support from parents, administrators, and teachers alike.

Bennett has not hidden behind a desk. He has personally visited more than 100 schools around the nation. In addition, he has given dozens of after-dinner speeches on the Republican fund-raising circuit, where his go-get-'em style is highly popular.

As a Cabinet officer, Bennett might have accomplished more if he had been more diplomatic and tactful. But he certainly got everyone's attention and spotlighted issues in vivid ways. However, for the long haul, education needs more than bombast. Cooperation is as necessary as confrontation, perhaps more so.

Whoever serves education secretary in the next administration - be it Republican or Democrat - will continue to be challenged by such headaches as drugs in the schools, dropouts, and the continuing poor performance of American students when compared to their counterparts in other countries.

Bennett may be leaving, but the problems aren't.