FIRST SOUTH AFRICA declares its "profound shock" that the American ambassador's little plane has been tooling around taking secret photographs. Then, mischievously, it leaks word that the same "spy plane" has been taking photographs in neighboring black African countries and pictures have been shared with Pretoria. There are supreficial inconsistencies between these developments, but there is a deeper core of consistency. They are signals that Prime Minister P. W. Botha may be planning to end the policy of seeking an accommodation with the West and to embark on a new policy of going it alone.

The new line appears to go like this: South Africa could profit greatly by swapping its economic and strategic assets for the West's company and understanding in the harsh racial and international passages that surely lie ahead. But if instead it is to be isolated and pressured, it might just as well move a step away from the United States-or from the Carter administration-and explore other possibilities. One such possibility is to tighten links with the moderate black-led multiracial regime just elected in Rhodesia and with the similar regime straining to take power in Namibia. Another possibility is to seek out anti-radical, anti-Communist friends in Africa and elsewhere. A third is to dangle South Africa's minerals and prospective independence before the Soviet Union, already an under-the-table trading partner.

The new line obviously has risks as well as benefits for South Africa. It is also butts head-on into a central administration premise. This administration has tended to think South Africa could safely be pressed to accept unpalatable American-sponsored solutions in Rhodesia and Namibia and even within South Africa itself because its only alternative was an inevitably building, Soviet-aided racial war. But Pretoria is now suggesting it has another choice: making do without the United States, or waiting out Jimmy Carter. No doubt part of this suggestion is bluff, but part of it-bolstered by much of white opinion-is real.

On Monday Mr. Carter said that he would take the month leading up to the inauguration of Rhodesia-Zimbabwe's new black prime minister to assess the elections there and that he would weigh their consequences as well as their conduct. He is right to proceed slowly and to take a comprehensive view. His southern Africa policies, however, well meant, have not adequately gained the parties' confidence, perhaps least of all South Africa's. The United States is losing the capacity to influence events. Earlier Mr. Carter offered to meet Prime Minister Botha after a Namibian agreement. Perhaps that meeting should be moved up. The spat over the "spy plane" shows how badly out of touch the two governments are.