THE CARTER ADMINISTRATION seems to be attempting a very complicated billiard shot in its nuclear nonproliferation policy. The President is simultaneously trying to placate the Europeans and the Japanese and get them to forego the breeder-reactor and plutonium-reprocessing technologies. He is also trying to persuade them not to contract to export these technologies to other countries and - at the same time - trying to assure the would-be importers, mostly Third World countries, that they are not being victimized by a conspiracy of industrialists who want to deny them modern means to advancement.

After some clumsy (and vain) efforts in the first few weeks of the administration to get two notorious export deals turned around - the German sale to Brazil and the French sale to Pakistan of extremely dangerous bomb-prone nuclear plant and technology - the administration seemed to adopt a new strategy. The President announced his own desire to defer, perhaps indefinitely, work in this country on the Clinch River breeder-reactor and the Barnwell reprocessing plant. But he seemed suddenly awash in deference and courtesy and understanding toward those Western European nations and Japan that seemed well-bent on going forward with the breeder and, much more importantly, with reprocessessing plants. He produced some proposed legislation dealing with our own export policy that many people felt was too mild to have much restraining impact on the nuclear activities of our friends. He freed up some stalled shipments of highly enriched uranium for use in foreign-research projects. He was sweet reason itself.

One way to look at all this is to say he simply has hold the pass. Another way is to say that Mr. Carter has finally recognized the fact that both the dangerous civilian technology and nuclear weapons themselves are going inevitably to spread so that trying to top the spread is pointless and unnecessarily divisive within the alliance. Carter administration people argue that both these assessments are wrong. Rather, they say, the President has recognized, in the words of a White House fact sheet, that "there is no such thing as an effective unilateral nonproliferation policy." For that reason, the argument goes, he does not favor some of the harsher measures currently being proposed. He is asking the Europeans and Japanese for time - time to demonstrate that plutonium reprocessing is economically questionable and time to work out the arrangements for an assured fuel supply and the storage of spent fuel, in ways that would not compromise any nation's independence. He believes, and rightly so, not just tht these things are eminently possible but also that there is no practical need or urgency whatever for the Europeans and Japanese to undertake the actual reprocessing of spent fuel for many years to come - if at all.

Did the President make any headway on this goal when he was in Europe? Presumably Mr. Carter wanted more from the conference than a pledge to get together and study the problem. We note with interest that German domestic political opposition to the development of the breeder reactor has compelled Bonn to slow down its research (even as a committee of the House here has gone against Mr. Carter's wish andvoted to continue teh Clinch River breeder project). These backs and forths suggest tht no one will know if the Carter approach is working for some considerable time, depending as it does on cooperative arrangements and decisions that can only come out of prolonged negotiations.

The point is this: Cooperativeness, understanding and sweet reason can add up to a very risky strategy. The administration could end up sweet-reasoning the Europeans and the Japanese right into a feeling that it is perfectly okay with us if they pursue the dangerous and ambiguous technologies. The test of the Carter strategy, in other words, will be how it uses the time it gets, how intensely it will go about demonstrating that there are infinitely better alternatives for the Europeans, the Japanese and the rest of the world than those now being pursued.