Washington holds its breath as events unfold in Mozambique. With Machel gone, US hopes for stability and move toward the West

The United States is watching anxiously -- and pretty much helplessly -- as uncertainty over the presidential succession in Mozambique adds yet another element of instability to an already volatile situation in southern Africa. What could be shaping up in the region is ``an interlocking crisis of fairly sizable proportion,'' says an informed United States official.

US analysts believe that a new Mozambican leader could continue the slow turn Westward begun by Samora Machel, who was killed in a plane crash Sunday.

On the other hand, they do not rule out the possibility that a new leader could take the country into a leftward plunge, and even invite Cuban troops into the country to prevent internal chaos. That could provoke a confrontation with South Africa, which is intent on preventing a Cuban presence on its eastern border.

The impact of Mr. Machel's death is difficult to assess, diplomats and other analysts here caution. And, they add, it could be aggravated by persistent attempts to blame either South Africa -- or the South Africa-backed Mozambique Resistance Movement (Renamo) -- for shooting down the plane in which he was traveling. (Renamo claims military victory is near, Page 11.)

A South African government official, who asked not to be named, says that an official board of inquiry has been set up to investigate the cause of the accident, and other countries have been invited to participate. Among them is the Soviet Union, which manufactured the plane and provided the pilot.

The preliminary indications are that bad weather and pilot error caused the crash, according to South African officials.

But the pilot, who survived the crash, insisted that the craft had been hit by something before it went down. The suspicion that South Africa or Renamo was behind the downing has already sparked riotous demonstrations in Harare, the capital of Zimbabwe.

The African National Congress (ANC), the leading South African resistance group, has blamed Pretoria for engineering Machel's demise.

Jackie Wilson, an official of the Washington Office on Africa, a lobbying group, says ``We're concerned with South Africa's possible role [and about] the incomplete information and the incongruous details.''

``All directions point to Pretoria,'' she says. ``It was in their interests to assassinate Machel. The first thing they want is a Mozambique that's out of control.''

South Africa has given backing to Mozambican rebels operating along the country's western border. The plane went down near the border.

Among possible successors to Machel, the names most frequently mentioned are Prime Minister Mario Machungo and Foreign Minister Joaquim Chissano. It is believed that either man would likely continue the slow turn toward the West begun by Machel.

But whoever the new leader is, he will be beset by problems immediately upon taking office, among them a deteriorating economy, continuing pressure from South Africa, and an upsurge of guerrilla violence.

Ms. Wilson theorizes that Machel's death was aimed at destabilizing Mozambique because it is the one country in the region with both a functioning rail system and access to the sea -- links that will become increasingly important as black front-line nations try to cut their links to South Africa. The goal of South Africa, she says, is to ``neutralize'' Mozambique.

South Africa signed a nonaggression pact with Machel in 1984, but even South African officials admit that Pretoria has repeatedly violated the agreement by providing support to Mozambican guerrillas trying to overthrow Machel.

While some analysts believe it is farfetched that South Africa would have directly engineered Machel's death, they did find it incomprehensible that, in one observer's words, ``South Africa had this air of smug satisfaction [when] Machel was on the ropes.''

``Our argument with the South Africans has been that Frelimo [the ruling party, which Machel headed] is better than chaos in Mozambique,'' says one analyst.

But, he predicts, ``South Africa will find a way to talk to its neighbors. It always has.''

The one move that could precipitate conflict would be if the new Mozambican leader invites Cuban troops, who are already in Angola, to help ensure stability and fight the Renamo guerrillas.

The South African government is said to believe that this would be a threat to its political and territorial ``heartland,'' and would take steps to prevent such a move. An informed source says that even a token Cuban force would be seen as the ``thin end of a wedge'' and would be firmly resisted.