Signs of unity in Chad weaken Libyan role. Government-rebel alliance could scotch Libyan designs on Chad

For the first time in 20 years, Chadians have more or less united in trying to drive out a foreign aggressor: Libya. A recent rally to the side of Chadian President Hissein Habr'e by the forces of Goukhouni Woddei, his main rebel opposition leader, has given the 20-year-old civil war in that country a new dimension.

The changed alliance has isolated the Libyan forces that were sent into northern Chad to aid Mr. Woddei's rebel's in their battle against the government.

This was French President Fran,cois Mitterrand's message to representatives from 40 African countries, including 20 heads of state, at the 13th Franco-African summit, held here late last week in the Togo capital.

Ending the war and driving the Libyans out of Chad would remove one of the main threats to the region's stability. It would be a great loss of prestige for Libyan leader Muammar Qadaffi and hinder his activities in other west African countries, according to diplomatic sources at the summit. It would also enable Chad, considered the poorest nation in the world, to concentrate on rebuilding its shattered economic infrastructure and raising living standards above subsistence levels.

An estimated 7,000 Libyan troops have been backing Woddei in his bid to oust President Habr'e. In 1979, Woddei was president of a transitional coalition government in Chad, but he is now head of the opposition provisional Government of National Unity (GUNT).

The change of alliances was sparked by tension between Woddei and Colonel Qadaffi which climaxed in a shooting incident in the Libyan capital late last month. The Chadian rebel leader was reportedly wounded when he attempted to evade being arrested by Libyan soldiers.

At a press briefing in Lome Saturday, Habr'e said that Woddei had ``completely cut links'' with Libya and that his estimated 3,000 troops had joined forces with the national troops. ``Together we are fighting the Libyan aggressor'' he said.

Habr'e called for international pressure to be brought on Libya to release Woddei, who is reportedly being held by Libya.

Reports indicate that heavy fighting is still going on in the Fada region of northeastern Chad between what Habr'e is now referring to as the ``Chadian forces'' and the Libyans. Recently, Habr'e accused Libya of practicing ``genocide'' in northern Chad. Entire villages are being destroyed and those villagers who survive the bombing and gunfire face death through famine or cold, the President said last week.

In the confusion brought on by the apparent turnaround of the Woddei forces, Habr'e has renewed efforts to convince France to back a push to recapture the northern territories from Libyan control.

Such a push would require that France, which has been involved in the civil war since the mid-1970s, military support above the 16th parallel. This dividing line between the Libyan-controlled north and the Habr'e-controlled south was established in 1983 by France, Chad's former colonial ruler.

But, France has refused to back a push into northern Chad, opting instead to increase supplies of arms and military equipment. Repeated efforts to end the war have foundered because both Habr'e and Woddei insist on being head of state.

French Prime Minister Jacques Chirac told journalists at the Lome summit that ``the conditions for French support are not likely to change in present circumstances.''

French sources say that a frontal assault under the present circumstances would be unwise and unnecessary, because the political momentum has swung in Habr'e's favor. They argue that the 1,200 French troops sent to Chad in February are there as a deterrent only.