As Sudan prepares for civilian rule, tensions with US deepen. But aid from US is likely to keep Sudan from shifting allegiance to Libya

On the eve of Sudan's return to civilian rule, Sudanese-American relations have deteriorated sharply. As with most Arab and African nations, the American attack on Libya April 15 brought an angry response from Sudan, in the form of official criticism and student protests.

The attack followed two other incidents that had already caused tension between the formerly close nations:

The alleged role the US Central Intelligence Agency played in arranging the clandestine airlift of refugee Ethiopian Jews to Israel in 1984 and '85. During the public trial of former Sudanese President Jaafar Nimeiry's vice-president, it was reported that the CIA paid huge sums of money to individuals in the old regime to aid the airlift.

Washington's public protest when the Sudanese Army borrowed Libyan aircraft to bomb insurgent forces in the south recently.

The largest country in Africa, Sudan holds a strategically important position in the horn of Africa. Its northern neighbor, Egypt, is a moderate Arab nation and a close ally of the United States. To the east lies Ethiopia under the Marxist rule of Col. Mengistu Haile Mariam and to the west Libya, led by radical Arab ruler Col. Muammar Qaddafi. Port Sudan on the Red Sea is vital to trade not only for Sudan but also for a number of its landlocked neighbors.

In reaction to the US attack on Libya, Sudanese trade unions have vowed not to unload US ships at port Sudan. However, this is likely to be more of a threat than a reality since Sudan depends heavily on American trade and aid. The country is among the largest beneficiaries of American aid in Africa, and is one of the five largest recipients of military aid. It also depends on US companies for the exploration and extraction of its potentially valuable oil deposits.

This strain in Sudanese-American relations is unquestionably serious. But national interest is bound to be a major factor in determining the new government's relations with Washington.

The new Sudanese government, which is expected to be formed by May 6, faces serious economic and security problems. It is therefore unlikely to shift its allegiance to Libya, thereby cutting off its only important sources of support from Egypt, the US, and, possibly, conservative Arab states as well, analysts say.

Sudan's newly elected constituent assembly met on April 26 to plan a civilian takeover from the interim head of state, Gen. Abdel Swareddahab, and the interim military and administrative councils that have ruled Sudan since President Nimeiry's overthrow a year ago. The assembly decided to extend the rule of the interim councils until May 6, by which time a proposed national unity government is expected to be formed by the ruling parties.

Although the results of this month's elections are not yet complete, it is already clear that the two traditional rival parties that had dominated Sudan's politics before Nimeiry took over in 1969 have again emerged the strongest groups. Neither, however, has a majority. Their attitudes toward Libya, Egypt, and the US differ, but not markedly.

The strongest party, with 99 seats so far declared, is Umma (``freedom''), the party of Sudan's dominant Islamic sect, the Ansar. Umma's leader, Sadiq Mahdi, is a direct descendant of the great Mahdi, ruler of Sudan's first modern unitary government in the late 1800s. He is a former prime minister and a graduate of Oxford University, England. The rival Democratic Unionist Party, with 63 seats declared so far, represents the minority Islamic sect, the Khatmia.

Despite their sectarianism, both parties are, according to experts in African affairs, nationalist and modern in their outlook. These two parties are expected to form a coalition government.

Their mutual political enemy, the National Islamic Front (Muslim Brotherhood), won more seats than was expected, with over 50. Most significant is the fact that they won 23 of the 28 seats reserved for university graduates. Their increased number is of great concern to those who fear any further moves toward Islamization in Sudan.

The communist and other radical parties have had surprisingly poor results so far. The communists won only three seats.

Little is known yet of the results in the mainly Christian and animist southern provinces, where elections in 37 of 68 districts were postponed because of civil unrest. In other southern districts, elections were boycotted by the influential Sudan People's Liberation Movement which, under Col. John Garang, has been waging an armed struggle against political domination by the northern Muslims and against any form of military regime.

Though the south has been struggling for decades for a fair say in the government of Sudan, the struggle against President Nimeiry and his successors has intensified under Colonel Garang.

With the emergence of a civilian government, however, Garang has promised that he will begin new negotiations on a democratic constitution for the country and ending the war in the south.

Apart from deciding on the composition of a new government, the constituent assembly is expected to handle the following issues:

Drafting a new democratic constitution for the country which, essentially, must determine a new relationship between the Islamic north and the largely Christian and animist south, as well as between the different regions in the north.

Ending the war in the south. The conflict has contributed to the country's sharp economic decline by, among other things, bringing a halt to drilling and pumping of oil on the fields opened up by Chevron and Gulf corporations.

An offer made late last week by Mr. Mahdi for the southern rebels to join in a national unity government has been rejected. Garang has, however, tacitly agreed to attend a conference which, Mahdi says, will be held to lay down the foundations of a settlement in the south. Garang maintains, however, that the conference should set up an interim administration and make arrangements for the holding of a fresh general election.

Tackling the country's economic problems, which have been aggravated by corruption, drought, famine, and the influx of three-quarters of a million refugees from Ethiopia and Uganda.

Deciding what to do about Sharia (Islamic law), imposed on the religiously-divided country by Nimeiry. This is one of the most sensitive issues. The Muslim Brotherhood would strongly resist any attempt at abolishing them. The Brothers want to go even further than Nimeiry in turning the country into an Islamic state.

Formulating Sudan's new foreign policy. Under Nimeiry, Sudan became closely linked to Egypt and the US, as well as to the conservative Arab Gulf states. His regime was bitterly hostile to Libya. The new leaders have already declared that Sudan's interests demand continuing friendly and close relations with Egypt. And Mahdi has stated that he intends to maintain ties with the United States as well as boost relations with Libya.