Little by little, the United States and the Soviet Union are edging toward a potential compromise on missile defense systems to thwart nuclear attacks. When President Reagan first talked about "Star Wars," with space rockets zooming in to blast enemy missiles, the superpowers were primarily targeting one another. Now the focus is changing. The two big countries see a more immediate threat in accidental, unauthorized or terrorist attacks, principally from Third World nations.
President Bush, flush in the middle of the Persian Gulf war when Iraq was brandishing its missile capability, announced last January he was refocusing the Strategic Defense Initiative to allow for "Global Protection Against Limited Strikes" or GPALS. In other words, not the all-out Soviet assault feared by Mr. Reagan. He proposed a $5.2 billion missile-defense program that called for land-based non-nuclear interceptors, an approach that is drawing increasing acceptance, and included funds for spaced-based interceptors, dubbed "Brilliant Pebbles," that are highly controversial.
In the House, Democrats cut off "Brilliant Pebbles" without a cent. But in the Senate, Armed Services Committee chairman Sam Nunn, D-Ga., engineered a compromise in which he won approval for the land-based missile defenses but wrapped space-based interceptors in elaborate ambiguity. There the matter rests in a Senate-House conference much affected by big-power diplomacy.