THE TRUSTEES of the University of the District of Columbia, together with its new president, Benjamin Alexander, are fighting for academic quality. In 1979, the trustees decided on probation and suspension standards, and now that the centralized computer system has finally made it possible to act on those standards, they have let the other shoe drop: of some 14,000 students, 880 have been suspended and 1,800 more put on probation. The UDC leadership could have flinched, softened the blow to avoid the predictable outcry; it didn't, and it was right.

President Alexander is "pleasantly surprised" that the early reactions by students to the academic hard line are "99 percent supportive." Those students recognize that if the open admissions policy is combined with some system of social promotions like that plaguing many public school systems, their UDC degrees will be debased. With the university reduced to little more than a second high school in the judgment of others, those students who had really done the work would be cheated -- cheated, among other things, of the increased opportunity a college degree should provide.

This is not a retreat on open admissions, but rather a necessary aspect of that policy. The way to address the weakness of entering students in a school like UDC should be with intensive extra help, patience as those students bring themselves up to competitive strength, and ultimate testing against academic standards designed to make them fully qualified graduates. That appears to be UDC's approach.

The support of the students, faculty and administrators at UDC for these newly announced painful measures is remarkable, especially because it demonstrates an aspect of the radical emphasis on quality education springing up around the country. That movement has both a conservative, back-to-basics strain, and a progressive theme: its declared and undeclared adherents are genuinely concerned that education, in particular public education, once again become an engine of economic upward mobility.

It was not long ago that a coalition of do-goods -- white and black -- nervous about being called "elitists" and more fearful of offending their charges than determined actually to give them the best schooling, would have balked at the hard choices. Such "solicitude" was shortsighted and ultimately harmful. Now it seems that at UDC the educational leadership has its eye on the future.