DID YOU KNOW THAT the most "modern" and destructive war ever fought between two states in black Africa is currently being waged? And that, aside from a little ineffective handwringing, nobody seems to be doing much to stop it? Somalia and Ethiopia are fighting in east Africa's Horn. Specifically, Somalia is sponsoring as assault on Ethiopia's Ogadan region, which it describes as "Western Somalia." The Somalis are supporting guerrillas of the "Western Somali Liberation Front," and they have engaged their own regulars directly. The outcome of the now seven-week-old war evidently depends in good measure on whether Somali can capture a handful of strategic towns before Ethiopia musters the resources available to it by reason of having a population almost 10 times as large and by reason of its new Soviet connection.

Most foreign interest in this war has centered on its "reversal of alliances." Ethiopia, long an American client, earlier this year fell out of the American orbit and began obtaining Soviet arms. Somalia, long (and still) a Soviet client, soon attracted the Carter administration's interest as a possible strategic offset to Ethiopia. Some officials, reportedly including the President, began relishing the prospect of reducing the Soviet presence across a broad swath of Africa and the Middle East on either side of the Red Sea. This was the basis on which, for a time, the prospect of American "defensive" arms was dangled before Somalia.

More recently, much of the gleam has gone out of the American eye. There is now a greater official appreciation of the difficulty of attempting to manipulate the turbulent forces wracking the Horn. More skepticism is being shown about the value of competing with the Russians for local position in this desolate corner. The earlier arms offer to Somalia has been shelved.

But the United States, still hoping to have Somalia's favor when the war is over, has not been able to bring itself to comment forthrightly on Somalia's responsibility for the war. Rather than risk giving offense, the State Department simple sidesteps the question. The result is that a country that by all the known facts is engaging in premeditated and unprovoked war against a neighbor, for the purpose of dismembering it, is getting a free ride. One is not surprised to find most other members of the United Nations averting their gaze from this spectacle. But one would have thought that the Carter administration could have found the moral fortitude to identify the Somalis' conduct for what it is: agression.