The decision by Egypt and the United States to rush military support to the Sudan within days of the single hit-and-run aerial bombardment on Omdurman has triggered off an urgent debate about the nature and source of that attack.
Ever since President Jaafar Nimeiry's regime began to feel threatened by the growing rebellion in the Christian-dominated southern part of Sudan, it has been urging President Hosni Mubarak to implement the Egyptian-Sudanese defense treaty. Simultaneously, it has been pressing the US to provide an airlift of arms.
Both Egypt and the US were reluctant at first to meet these requests because they did not wish to become involved in the Sudan's internal armed power struggle that began almost a year ago.
Following divided counsel in the US State Department and the Pentagon, Gen. Vernon Walters was sent to Sudan last week to carry out one of his by now familiar independent military assessments. At about the same time, on March 11, Presidents Nimeiry and Mubarak met at Aswan, where the Egyptian leader reportedly explained that their defense treaty did not allow for Egyptian interference in what was an internal affair.
The March 16 attack on Omdurman (one of the five towns that constitute the capital, Khartoum) therefore came as a godsend to Nimeiry. By claiming that the attack was made by Libya, he provided the external dimension needed to invoke the Egyptian-Sudan military agreement, and touched the right nerve in Washington that led to the decision to send two airborne warning and control system (AWACS) planes to Egypt this week.
Libya, though, has denied any responsibility for the attack, blaming it on rebels in the Sudan Air Force.
There is also strong support for a third view: that Nimeiry himself ordered the attack to force his reluctant Egyptian and American allies to come to his aid.
This last suspicion is not as preposterous as it seems. First, there is a dispute about the type of plane used in the attack. Nimeiry claims it was a Soviet light bomber, a Tu-22; but competent eyewitnesses insist it was a MIG-15, which has a much smaller flying range.
More important, though, is the undisclosed fact that one of the three houses bombed in Omdurman was the family home of the detained opposition leader and former Prime Minister Sadiq al-Madhi. Besides, the official claim that Khartoum's radio station was the main target failed to disclose that the building which was only lightly hit was the old radio station.
Clearly, there are important questions needing clarification before the official version of the attack is accepted.
The threat to Sudan has developed rapidly since Nimeiry decided to introduce Islamic laws and decreed Sudan an Islamic republic last November. These policies seriously upset not only the Christian-dominated southern provinces but many Muslim northerners as well.
This Muslim opposition is of two kinds: the influential, radical secularist elite object to their country being turned into a theological state, while rival groups of Islamic fundamentialists object either because they feel that the Islamic reforms don't go far enough, or because they have been introduced without proper consultation.
The Islamization proposals were seen by many southern leaders as the last straw. Revolt had already begun because of an earlier decision to divide the federally autonomous region of the south into its three original provinces - Upper Nile, Equatoria, and Bahr el Ghazal.
After nearly a year of fighting in the south, military engagements are now approaching the scale of full battles, with thousands already killed on both sides. And the country's already shaky economy has been badly hit by the decision of US oil firms to suspend operations in the Bentiu area because of security problems.
In addition, the French contractor building the Jonglei Canal, Compagnie Centrale Internationale, decided to halt construction. The decisions came after attacks on workers engaged in these projects.
Information is only now reaching the outside world about the nature of the rebel movement and its leadership. Hitherto, it was assumed that all the rebel activity was the work of the resurrected Anya Nya Movement, which led a 17-year struggle for the autonomy of the south.
That struggle finally ended with the signing of the Addis Ababa agreement in 1972, which gave southern Sudan considerable autonomy. To emphasize the resumption of the earlier struggle, leaders of the new revolt at first called themselves Anya Nya Two Movement.
However, an entirely new political movement and fighting force have been created, distinctly different from Anya Nya Two. The Sudan People's Liberation Movement (SPLM), and its fighting force, the Sudan's People's Liberation Army (SPLA) reject the secessionist aims of Anya Nya, and see the struggle as ''a national struggle'' involving all Sudanese: Muslims and Christians, northerners and southerners.
The rebels' leader is a young Army officer, Col. John Garang de Mabior. He is one of 22 senior officers who have absconded from the national Army, along with an estimated 6,000 privates. This trained, professional military force forms the core of the rebel army that is being rapidly mobilized and trained in the south. Its strength is now reported to be over 7,000.
The SPLA has appealed to the Anya Nya Two rebels to join them. Many have done so, but by no means all. This has led to some difficulties between the rebel forces.
However, the old secessionist feelings among many southerners live on. But antisecessionist views are reported to be strong, especially among the younger, better-educated southerners who are behind the SPLM.
The SPLM's declared policy is not to harm foreigners working in the south, nor drive away foreign firms developing the oil industry and building the Jonglei Canal.
In letters to Chevron and Compagnie Centrale Internationale, the SPLM said it wishes to maintain the installations and property, but demands that the companies should, in the future, complete their negotiations with the SPLM and have no further dealings with the Sudan government concerning any activities in the south.
Joseph Oduho, chairman of the SPLM's political and foreign affairs committee, said in an interview in London this week: ''We want to persuade Britain and other European governments to intervene with Washington not to repeat its old mistake of intervening on the side of a tottering regime. The Americans should stay out of our internal conflict. We are not communists or anti-Western; we are nationalists who believe that through socialism we can unite our country.''