The Democratic Unionist Party (DUP) was similarly based on a religious order, the Khatmiyyah organization. Ever since the Khatmiyyah opposed the Mahdist movement in the 1880s, it has been a rival of the Ansar. Although the Khatmiyyah was more broadly based than the Ansar, it was generally less effective politically. Historically, the DUP and its predecessors were plagued by factionalism, stemming largely from the differing perspectives of secular-minded professionals in the party and the more traditional religious values of their Khatmiyyah supporters. The DUP leader and hereditary Khatmiyyah spiritual guide since 1968, Muhammad Uthman al Mirghani, tried to keep these tensions in check by avoiding firm stances on controversial political issues. In particular, he refrained from public criticism of Nimeiri's September Laws so as not to alienate Khatmiyyah followers who approved of implementing the sharia. In the 1986 parliamentary elections, the DUP won the second largest number of seats and agreed to participate in Sadiq al Mahdi's coalition government. Like Sadiq al Mahdi, Mirghani felt uneasy about abrogating the sharia, as demanded by the SPLM, and supported the idea that the September Laws could be revised to expunge the "unIslamic " content added by Nimeiri.

By late 1988, however, other DUP leaders had persuaded Mirghani that the Islamic law issue was the main obstacle to a peaceful resolution of the civil war. Mirghani himself became convinced that the war posed a more serious danger to Sudan than did any compromise over the sharia. It was this attitude that prompted him to meet with Garang in Ethiopia where he negotiated a cease-fire agreement based on a commitment to abolish the September Laws. During the next six months leading up to the June 1989 coup, Mirghani worked to build support for the agreement, and in the process emerged as the most important Muslim religious figure to advocate concessions on the implementation of the sharia. Following the coup, Mirghani fled into exile and he has remained in Egypt. Since 1989, the RCC-NS has attempted to exploit DUP factionalism by coopting party officials who contested Mirghani's leadership, but these efforts failed to weaken the DUP as an opposition group.

Data as of June 1991