During the early years of the Republic, despite political divisions, a parliamentary system was established with a five member Supreme Commission as head of state.

Before 1955, however, whilst still subject to the condominium, the autonomous Sudanese government under Ismail al-Azhari had temporarily halted Sudan's progress toward self-determination, hoping to promote unity with Egypt.

Despite his pro-Egyptian National Unionist Party (NUP) winning a majority in the 1953 parliamentary elections, Azhari realized that popular opinion had shifted against such a union.

The Transitional Constitution also allocated executive power to the prime minister, who was nominated by the House of Representatives and confirmed in office by the Supreme Commission.

The government placed Sudanese in the administration and provided compensation and pensions for British officers of Sudan Political Service who left the country; it retained those who could not be replaced, mostly technicians and teachers.

Khartoum achieved this transformation quickly and with a minimum of turbulence, although southerners resented the replacement of British administrators in the south with northern Sudanese.

Washington hoped this agreement would reduce Sudan's excessive reliance on a one-crop (cotton) economy and would facilitate the development of the country's transportation and communications infrastructure.

Major issues confronting Khalil's coalition government included winning agreement on a permanent constitution, stabilizing the south, encouraging economic development, and improving relations with Egypt.

The Umma, for example, wanted the proposed constitution to institute a presidential form of government on the assumption that Abd al-Rahman al-Mahdi would be elected the first president.

In the south, the vote represented a rejection of the men who had cooperated with the government—voters defeated all three southerners in the preelection cabinet—and a victory for advocates of autonomy within a federal system.

Resentment against the government's taking over mission schools and against the measures used in suppressing the 1955 mutiny contributed to the election of several candidates who had been implicated in the rebellion.

Unfortunately, factionalism, corruption, and vote fraud dominated parliamentary deliberations at a time when the country needed decisive action with regard to the proposed constitution and the future of the south.

When he presented the pact to parliament for ratification, he discovered that the NUP wanted to use the issue to defeat the Umma-PDP coalition and that many PDP delegates opposed the agreement.

Its failure to place capable civilian advisers in positions of authority, or to launch a credible economic and social development program, and gain the army's support, created an atmosphere that encouraged political turbulence.

The police killed three people in their attack; two students, Ahmed al-Gurashi Taha from Garrasa in the White Nile and Babiker Abdel Hafiz from Wad-Duroo in Omdurman, and a University of Khartoum manual labourer, Mabior, from the southern part of Sudan.

According to Mahmoud A. Suleiman, deputy chairman of the Justice and Equality Movement in 2012, "the main reason for the October Revolution was the Sudanese people's dislike of being ruled by military totalitarian regimes.

The SANU, founded in 1963 and led by William Deng and Saturnino Ohure – a Roman Catholic priest – operated among refugee groups and guerrilla forces.

After the collapse of government-sponsored peace conferences in 1965, Deng's wing of SANU—known locally as SANU-William—and the Southern Front coalesced to take part in the parliamentary elections.

Exiled SANU leaders baulked at Deng's moderate approach to form the Azania Liberation Front based in Kampala, Uganda.

By October 1965, the Umma-NUP coalition had collapsed owing to a disagreement over whether Mahjub, as prime minister, or Azhari, as president, should conduct Sudan's foreign relations.

The latter group professed loyalty to the Imam's nephew, the younger Sadiq al Mahdi, who was the Umma's official leader and who rejected religious sectarianism.

The Sadiq al Mahdi government, supported by a sizeable parliamentary majority, sought to reduce regional disparities by organizing economic development.

The educated elite and segments of the army opposed Sadiq al Mahdi because of his gradualist approach to Sudan's political, economic, and social problems.

Their resentment of Sadiq increased when he refused to honour a Supreme Court ruling that overturned legislation banning the SCP and ousting communists elected to parliamentary seats.

Despite this apparent boost in his support, Sadiq's position in parliament had become tenuous: concessions he had promised to the south in order to bring an end to the civil war were not agreed.

The Umma traditionalist wing opposed Sadiq al Mahdi: they argued strongly against constitutional guarantees for religious freedom and his refusal to declare Sudan an Islamic state.

Because it lacked a majority, the DUP created an alliance with the Umma traditionalists, who received the prime ministership for their leader, Muhammad Ahmad Mahjub, and four other cabinet posts.

The coalition's program included plans for government reorganization, closer ties with the Arab world, and renewed economic development efforts, particularly in the southern provinces.

When it refused to participate in efforts to complete the draft constitution, already ten years overdue, the government retaliated by closing the opposition's newspaper and clamping down on pro-Sadiq demonstrations in Khartoum.

The communists and other leftists aligned themselves behind the presidential candidacy of former Chief Justice Babiker Awadallah, whom they viewed as an ally because he had ruled against the government when it attempted to outlaw the SCP.