THE SPRINGBOKS, a South African rugby team, are scheduled to play in the United States --and why not? Everything South African raises, inevitably, a certain moral and political question. But the answer is not to mimic the tactics of a police state and bar privately invited, legal visitors, as some now urge President Reagan to do. Nor is to do as Mayor Koch has done in New York, cancelling a match there with the explanation that police protection would be too difficult.

The case against admitting the Springboks is that South Africa is a racist state, and therefore isolation of its rugby team is both a moral imperative and an effective protest against apartheid. That case is augmented by the disclosure that a wealthy South African, Louis Luyt, donated $25,000 last December to the Eastern Rugby Union of America, the sponsor of the Springboks' tour. Mr. Luyt was earlier an active participant in a secret campaign to use millions of dollars of his government's money, without disclosing the source, to buy better publicity and public relations abroad for South Africa. When this campaign became public, a prime minister was forced out of office.

Mr. Luyt's donation raises all the familiar questions about the use of money, public or private, in international athletics. It's useful to remember that all of these questions--and they aren't getting any simpler, from year to year--regularly come to a quadrennial climax in the Olympics. It's a fair guess that about three-quarters of the Olympic medals go to athletes principally supported by government money for reasons of government policy--that is, propaganda. Olympic organizers, in this country and the other democracies, have long since acknowledged, with endless deep sighs, that it is neither desirable nor possible to try to exclude athletes on grounds of the sources of their support, or the moral tone of their governments.

It is quite true that apartheid is morally repellent. But is the United States to deny the South Africans visas this year, and yet grant visas in 1984 to the Soviet Olympic team? How about the Argentinians and the East Germans and the Chileans? How about Taiwan, and China's obsessive campaign to exclude its athletes and its flag?

Those people who feel strongly about South Africa and its rugby team have a right not only to stay away from the matches but to ask their fellow citizens to stay away. Sports, like the arts, offers individuals the opportunity to make their own choices; the size and character of an audience constitute a public judgment. Orderly and peaceful protests are surely in order in Albany and Chicago, the other cities where the Springboks are scheduled to play.

Perhaps it's also relevant that athletics is, in South Africa, dominated by racial discrimination less than most other endeavors. Unquestionably, South Africa uses its integrated teams as political instruments--a fact that vitiates South African complaints that its teams are the victims of politics. But you don't necessarily have to consider the integrated teams to be the wave of the South African future to laud and encourage the modest progress they represent. Nor do you necessarily underestimate apartheid when you conclude that, on balance, excluding the Springboks would do more damage to American traditions than to South Africa's.