UNDER AN AMENDMENT approved by the Senate last week, the Department of Health, Education and Welfare will no longer be able to require school systems to bus students in order to achieve school desegregation. The Eagleton-Biden amendment closes a two-year-old loophole and strips HEW of a basic tool for desegregating schools. The Senate action follows House approval of a similar measure.

Civil-rights forces, justifiably, plan to challenge the constitutionality of the amendment if it becomes law. They contend that it requires HEW to fund segregated school systems: such a requirement, of course, would be patently unconstitutional. Indeed, the Eagleton-Biden amendment is part of a shabby shell game Congress has played for years. Voting for measures like this may help a legislator preen his anti-busing image, but it contributes nothing to resolving the vexing question of how to achieve school desegregation with minimal controversy and inconvenience.

From the brouhaha in Congress, you might think that massive numbers of school children are bused to foster desegregation. In fact, according to the best estimates, only 4 per cent of the nation's bused students are bused as part of a desegregation plan. The rest are bused for others reasons - distance, safety, convenience and so on.

These anti-busing amendments imply that HEW has been heavy-handed in its dealings with school systems. But the evidence suggests this is not so. HEWS's actions have been minimal compared to those of the federal courts. And by negating HEW's power to act against segregation in school systems, the amendments will force more cases into the federal courts, where decisions often are less politically sensitive than are HEW's administrative orders.

True, HEW could skirt the intent of the Eagleton-Biden amendment by carrying out its constitutional duty and notifying school districts found in violation of Title VI that they will lose their federal funds unless they desegregate. It wouldn't tell the districts they had to bus students and would have the accomplishment of desegregation entirely in their hands. But, to judge by past experience, we doubt that Congress would appreciate either the controversies or the bitterness that such orders would create.

What the Congress really is doing is denying the possibility for equal educational opportunities to minority youngsters trapped in ill-equipped inner-city schools. For example, Sen. Eagleton sponsored not only the anti-busing amendment but an amendment to cut $165 million in Title I funds. These funds help children who are educationally and economically disadvantaged. Fortunately, the Senate cut only $65 million.

There is growing disenchantment with busing. But Congress cannot simply help to create a Catch-22 situation that compounds the evils busing was designed to cure. If busing is an unacceptable way of solving problems of segregation and unequal educational opportunities, allocation of greater resources to beleaguered inner cities with shrinking tax bases becomes urgent.