WHO IS SURPRISED to learn that once again an American administration ostensibly devoted to preventing the spread of nuclear bombs to other countries has yielded to India's insistence on going its own nuclear way? This has been the pattern of Indian-American relations since 1974 when the Indians exploded a bomb, calling it (as they do to this day) a device not a bomb, an explosion for peaceful purposes.

In the latest instance, India had been pressing the United States to sell it spare parts for its American- built nuclear power reactor at Tarapur. The United States had refused, as it must refuse under a 1978 law blocking nuclear transactions with countries whose nuclear facilities have not been placed under the international controls designed to ensure that countries do not divert peaceful nuclear activities into weapon-making. The Indians, however, kept pressing. There were, as a news report put it, "months of acrimony." And now, for the sake of "removing an irritant," the United States has agreed to supply the spare parts.

Actually, it is not clear what the United States agreed to. Secretary of State Shultz, in India, indicated the Indians could acquire the parts in this country, while his spokesmen said the United States would arrange for India to acquire them in a third country. The latter route is the one followed a year ago when, to help India circumvent the American legislative ban --as usual in the name of "improving" Indo-American relations--the United States arranged for India to acquire a new batch of reactor fuel in France.

"We are satisfied" with the new arrangements, the Indians said. They bloody well ought to be. Once again they have advanced their independent nuclear program without suffering the indignity or inconvenience of accommodating to either American or international standards. In one more eyeball-to-eyeball encounter on nuclear policy, they have made the United States blink.

Something more is involved here than American pride. Many countries have peaceful nuclear programs that would help them make bombs if they chose. But of all those countries with such peaceful programs, only India has actually gone the distance to an explosion--although others are either capable of it or on the verge. As unsteady as the world is today, a world in which a constantly growing number of nations possessed nuclear weapons would be a great deal more unsteady, at least from an American point of view. How can the United States expect others to take it seriously on nonproliferation when it keeps caving in to India?