AGAIN SOMEONE dies in the Kremlin who appears to be terribly important but whom scarcely anybody in the West has even met. The penchant for personal anonymity is typically Soviet and typically disconcerting to Westerners, who regard it as of a piece with the hiding away of missiles, only less defensible. This time the object of our blank stares is Dmitri Ustinov, 76, the minister of defense and Politburo member. Barely 30 years old, he was put in charge of producing Soviet armaments in World War II -- an assignment he perhaps owed less to his demonstrated achievements than to the fact that Stalin had murdered all the likelier appointees in the Great Purge. He has since been known as Mr. Soviet Military-Industrial Complex, but on the civilian side. The title of marshal was pinned on him late in life. Presumably the real marshals were not too happy about it.

That was always the question about Mr. Ustinov, and about the way the post-Stalin Kremlin runs defense: Are there any real limits to it? Is there a civilian authority with different and broader goals than the military and with the power to impose that civilian view (if there is one)? One would think that if anyone could do it, it would be Mr. Ustinov, the peer in age, the partner in the great enterprise of the war and later the close associate of the top military men for more than four decades. Mr. Ustinov himself presided over the building of a defense force second, as he insisted, to none -- and over its aggressive use in Afghanistan and in shooting down the KAL airliner.

Mr. Ustinov's death unquestionably alters the internal Kremlin balance of forces (in ways we can only guess about) and moves the hardy corps of old men who rule the Soviet Union a notch closer to the long-awaited takeover by a younger generation. It will be a generation not familiar, as Mr. Ustinov was, with Stalin's madness, and not given to his ready allusions to World War II. Will the new group be more objective, less besieged? Mr. Ustinov accompanied Leonid Brezhnev to Vienna to meet Jimmy Carter in 1979 and gave his counterpart a stuffed bear (symbol of the Soviet Olympics), saying the Soviet bear "is threatening only in evil times -- in general he is good and peace-loving."

Later -- but still in 1979 -- he showed a faint glimmer of understanding that Soviet muscle-flexing might provoke a foot-to-the-floor American response that would nullify Soviet advances in arms and create large new difficulties. If this was in fact his perception, one can hope that the next leadership generation shares it. The immediate choice to succeed him, Marshal Sergei Sokolov, is old (73), a military man and not in the Politburo -- evidently a transitional figure, and even more of an unknown.