THE LATEST victim of Libya's Muammar Qaddafi is the Organization of African Unity. His support of insurgents in the Western Sahara was partly responsible for the body's inability to hold its annual summit last August, and his support of insurgents in Chad was chiefly responsible for the OAU's second summit collapse last week. On neither occasion could the OAU obtain the requisite two-thirds quorum. Col. Qaddafi took his position despite the fact that the summit was to be held in his capital and, unless it were held, he could not assume the prestigious position of OAU chairman. He was ready to sacrifice Africa's premier regional institution to advance his revolutionary goals.

True, Col. Qaddafi is acting in a regional context in which the United States and France, among others, have actively supported conservative regimes, such as Morocco, notably in Western Sahara, and helped organize resistance against radical Soviet-supported regimes such as his own, notably in Chad. He can fairly claim that his 1980 intervention in Chad, at the then-ruler's request, was in accordance with an OAU mandate. He pulled his troops out of Chad -- though not all the way -- in 1982 when asked by the current president, Hissene Habre, whose backers include Egypt and the United States.

Col. Qaddafi, however, has sponsored terror, insurgency or other forms of intervention in a dozen or more African states. He has no supportable basis for continuing to claim and occupy a mineral-rich stretch of northern Chad. Only three African countries joined him in backing Hissene Habre's arch rival for Chad's OAU seat. The responsible regional thing to do would have been to allow President Habre to be seated and to permit the organization to conduct its normal business. Instead, the Libyan leader took an unnecessary and provocative stand on the representation question, which is an especially troublesome one to a continent full of regimes that came to power by conquest or coup. The OAU is paying the price.

If the deterioration is not arrested, Africa itself will pay. For its 19 years, the OAU has successfully helped its members maintain their national and territorial integrity within their arbitrary colonial borders. The organization has represented the continent's intent to protect itself from foreign intervention and manipulation and, specifically, to avoid becoming simply an East-West checkerboard of "radical" and "moderate" states. It has been the vehicle for what formal unity black Africa has attained on ending white supremacist rule in South Africa. All this Col. Qaddafi would spoil.