THE PRESENT NARROW, frightened government of South Africa seems determined to undermine what vestigal free institutions remain in the country and to turn itself by degrees into a Soviet-style totalitarian state. The latest evidence of this disheartening trend lies in the "press code" that Prime Minister Vorster has just introduced in Parliament, which is controlled by the increasingly reactionary right wing of his Nationalist Party. Long frustrated by the press' determination to report and comment in the Western tradition, the government has finally decided that its policy of harassment must give way to outright suppression of free inquiry.

"Press code": the words sound innocuous. The reality would be to put an immense amount of crude power over the media into the government's hands. The government would appoint a majority of the members to a press council, which would function as a kind of kangaroo court, imposing sanctions, including criminal sanctions, on owners, editors and journalists found guilty of violating the government's standards of journalistic responsibility. There could be no appeal of this council's decisions to the South African judiciary, which happens to be the society's one other outpost of freedom. Newspapers, for instance, would have to "exercise exceptional care and responsibility as to subjects that may cause enmity or give offense in racial, ethnic or cultural matters . . . matters that may detrimentally affect the safey of the State, the common weal, the peace and good order and the defense of the Republic . . ." What self-respecting journal could last a week stretched out on this sort of puritanical rack?

We note that not only the outspoken English-language press of South Africa and, of course, the courageous black press, but even the more conservative Afrikaans-language press are united, at least initially, in opposing this assault on their tradition and effectiveness. They deserve the support of all people concerned with free institutions and the struggle for racial justice in South Africa. For what is at stake here is not merely the condition of one institution. Announcement of the press code signals the government's readiness to turn a deaf ear to those South African voices crying out for change to preempt catastrophe. It means the practical end of the government's belief that, by maintaining itself in some aspects as a democratic society, it could present itself as fit for Western political and social company. It amounts to acceptance of confrontation at home and isolation abroad.

Jimmy Carter's arrival at the White House has newly sensitized the entire international community to the human rights question. He has made it clear that the United States will move its own policy closest to those nations that share its values. A substantial number of countries have altered their policy, at least in a token way, since he took office. Though the press-code proposal is not yet law, South Africa seems determined to go the other way.