WHEN Andrei Gromyko briefs Konstantin Chernenko about the South Pacific, my guess is that he has to take a map along to point out New Zealand. Neither in Moscow nor Washington does New Zealand loom in the forefront of global concern.
It is an idyllic land, southeast of Australia, with a population of decent, unpretentious people descended mainly from the British. Even so, they maintain a good-natured independence from the English ``Pommies,'' as they do from the ``Yanks,'' whom they basically like, and from the Australians, whose vigor and sophisticated economy make the New Zealanders, who live well, but without stress, slightly uneasy.
New Zealanders enjoy one of the most spectacularly beautiful lands in the world, from scenic Auckland and their wind-swept capital of Wellington, on the North Island, to the mountain-girt lakes of the South Island, and the glaciers on which carefree local pilots land skiplanes full of breathless tourists. New Zealand is famous for (1) Sir Edmund Hillary, the conqueror of Everest; (2) sheep, of which there are many; and (3) rugby football, which is the national passion.
It is a tranquil paradise, with no strategic significance or present threat. Yet what New Zealand has done, or specifically what its new Labour Party prime minister has done, is to cloud its hitherto satisfactory relationship with the United States and cast a deep shadow over the ANZUS treaty, which binds the US, Australia, and New Zealand in a mutual defense pact.
Prime Minister David Lange swept to power last July proclaiming his support for the South Pacific alliance and a cordial relationship with Washington, but he was hobbled by his party's antinuclear policy and its eagerness to bar all nuclear-powered or armed ships from New Zealand's waters.
The American response was to play it cool, to give Mr. Lange the opportunity to work out his problems with his party. Thus no American warships were scheduled for visits to New Zealand for the rest of 1984. Not until recently was the formal request made for the destroyer Buchanan to visit New Zealand in March. Even then, the destroyer offered up was conventionally, and not nuclear, powered.
But though the US had finessed the problem of a nuclear-powered ship, the issue of nuclear arms remained. Mr. Lange insisted on a US declaration that the Buchanan carried no nuclear weaponry. This the US could not do. It never indicates which of its ships carry nuclear arms. The reason is simple: You do not pinpoint for a potential enemy which of your vessels around the world are nuclear armed. Mr. Lange could not tolerate this ambiguity. So the visit is off, and two countries that cannot exchange port calls do not seem to have much of an alliance anymore.
As a sovereign country, New Zealand can decide whom it wants for its allies. The US had hoped that Mr. Lange would exercise the same statesmanship as has been displayed by Margaret Thatcher and Chancellor Helmut Kohl in dealing with the peace-at-any-price crowd in Western Europe. Even a sturdy Socialist like Franois Mitterrand has proved steadfast in holding the line against Soviet nuclear blackmail.
But as one foreign leader says harshly, you have to use a microscope to see Mr. Lange's political backbone. The sensible compromise for which the US hoped has so far eluded Mr. Lange's political skills.
The problem is that Australia, too, has an antinuclear lobby, which would like to see US ship visits curtailed. Aside from the problem of nuclear weapons, some 60 percent of American warships are now nuclear powered. If the ban spread from New Zealand to Australia, and Japan, and other countries, the United States Navy's ability to operate around the world would be badly hindered.
So what now? The New Zealand situation needs deft handling by the US. The fact is that strong allies of the US get better treatment, particularly at the hands of Congress, than nonallies. New Zealand will probably pay a price for moving out of allied ranks. But if it is no longer to be an ally, New Zealand is certainly no enemy and should not be treated like one. It is a friend. Though few in number, New Zealanders fought with valor alongside Americans in World War II. They were in Korea. And in Vietnam.
All this counts for something and will outlast Primer Minister Lange's tenure.