THE United States may be coming to the end of the line on mandated school busing for desegregation purposes. Many school districts have cases moving through the courts to rid themselves of long-imposed mandated transportation plans. States like California have already passed initiatives to limit busing requirements. And the Reagan administration - which has, until recently, merely bucked lawsuits that would expand busing programs - recently went a step further , urging that court-ordered busing be ended in elementary schools that have met their legal desegregation obligations.
Busing has never been politically popular. In some places, such as Boston, it has been a highly volatile issue that divided neighborhoods and spurred bitter controversy. In other cities, including Charlotte, N.C., busing was carried out peaceably and has worked relatively well.
But even many of those who have reservations about specific school transportation plans admit that busing has generally accomplished what it was intended to do: desegregate the nation's schools.
The basic questions now are: If court-ordered busing is abolished, will school districts resegregate themselves? Or with the memory of busing still uppermost, will they continue to maintain racial balance - using state plans and voluntary programs to achieve a racial mix in the classroom?
Resegregation would be unfortunate. It would tend to confirm the worst fears of minorities and civil rights leaders that there is today retrenchment from the social gains of minorities during the the 1950s and '60s. And further, it would indicate to some that government is lending at least de facto approval to racial bias.
On the other hand, a voluntary commitment to continued school integration by both government and individuals could be an important next step in obliterating prejudice and ending even lawful facets of separation of racial and ethnic groups.
A case to watch is now in the Fourth US Circuit Court of Appeals in Virginia. It could end up in the US Supreme Court, and if it does, the landmark 1954 Brown v. Board of Education decision outlawing school desegregation might be significantly modified.
In the appellate action, civil rights groups, on behalf of black schoolchildren in Norfolk, Va., are challenging a US district court ruling that abolished a longstanding court-ordered busing plan there. The lower court held that this school system, which is 60 percent black, had complied with desgregation orders for more than 13 years - and that it was time to lift the yoke of a mandated transportation plan.
The US Justice Department has filed a legal brief that supports the shelving of the busing requirement. In it, assistant attorney general William Bradford Reynolds lays out the Reagan administration's official stance. In short: (1) School districts that have met their legal obligation to desegregate should be allowed to go it alone without further court scrutiny, and (2) authority for running public schools should be returned to local officials.
An end to busing would help reestablish inner-city neighborhood schools and encourage parental involvement in them, the Justice Department asserts. Eliminating such cross-town transportation of minorities would also end white flight to suburban public schools and private institutions, government lawyers insist.
Civil libertarians, on the other hand - including the National Association for the Advancement of Colored People and the American Civil Liberties Union (ACLU) - believe the elimination of busing requirements would open the door to resegregation. They accuse the Reagan administration of knuckling under to the segregationists. A lawyer for the black children has called the move to stop busing an ''attempt to overrule Brown (Brown v. Board of Education), pure and simple.''
Some experts see the Norfolk case as more a symbolic than a significant legal move that could pave the way to wholesale garaging of school buses nationwide. ACLU's Burt Neubourne says, ''It's hard to believe that most courts (across the US) will back away from busing without reassurance of alternate mechanisms to preserve desegregation.'' The mechanisms he is referring to include magnet schools, withholding of state and federal aid from those that don't desegregate, and grass-roots voluntary programs promoting racial mix.
But what's clear, Mr. Neubourne insists, is that the Justice Department is now ''captured by people who don't care about integration.''
Neal Devins, a civil rights specialist, says the main issue for the courts now is whether the decision of districts to return to neighborhood schools is in itself ''intentionally discriminatory.'' And he warns that antibusing advocates may try to use the Norfolk case, among others, to establish that busing leads to white flight. ''Such a finding could undercut desegregation,'' Mr. Devins says.