Parliamentary group leader in the national Constituent Assembly of Omdurman. In 1988, the SSPA joined other Southern and Nuba parties in a coalition called the United Sudan African Parties (USAP) that took the lead in organising dialogues with the rebel Sudan People’s Liberation Movement (SPLM). Ukel became a minister of local government in the final coalition government of prime-minister Sadiq al Mahdi (25 April – 30 June 1989). After the June 1989 coup, USAP was banned like all other parties and went underground. Ukel helped to form the domestic arm of the exiled National Democratic Alliance (NDA), an umbrella of parties and forces opposed to the “National Salvation Revolution” rule of General Omar al-Bashir, and was appointed its secretary general in 1992, while still working as a teacher of English language. When USAP chairman Hilary Logali passed away in 1998, Ukel became his successor. During this period, he was repeatedly detained by al-Bashir’s government, the last time between December 2000 and October 2001 on charges of treason and sedition. Ukel and Alier participated and mediated in the peace talks between the SPLM and al-Bashir's government in Naivasha, Kenya, which led to the Comprehensive Peace Agreement (CPA) in 2005. Under its power-sharing agreement, USAP was allocated ten seats in the National Assembly and Ukel was appointed Minister of Parliamentary Affairs in the Government of National Unity. In its campaign for the 2010 general elections, USAP defined as one of its main goals “unity in diversity” as opposed to separation, which it emphasized by the choice of Khartoum as its headquarters. It failed to win any parliamentary seats, complaining about illicit actions against its campaigning. Nevertheless, Ukel was appointed the Minister for Higher Education in the Government of Southern Sudan (GOSS). After the independence of South Sudan in July 2011, Ukel was appointed Minister of General Education and served in this office until President Salva Kiir dismissed the whole cabinet in August 2013. In the 2014 IGAD-led peace talks with the rebel SPLM-IO, Ukel was part of the government delegation, representing smaller opposition parties. In April 2017, Ukel as USAP chairman was one of nine candidates picked by the government to represent South Sudan at the East African Legislative Assembly. The same month, he was selected by Kiir as a member of the steering committee for the National Dialogue. However, he was not elected by the Transitional National Legislative Assembly in Juba