Even during his lifetime...
Even during his lifetime, however, Muhammd Ahmad had designated a qadi al-Islam to administer his legal decisions. There were not enough Jews or Christians (other than British soldiers) in Sudan during the Mahdiyah to require an official policy; but there were plenty of Sufis, and in fact Muhammad Ahmad had been a member of the Khatmiyah order and Sufis of that and other orders made up a substantial part of his following.
However, that did not prevent the Sudanese Mahdi from dissolving all Sufi orders upon his accession to power-although their reappearance after the Mahdist state's conquest by the British in 1898 shows that the Mahdi was not omnipotent. It is for attempts at Pan-Islamic universalism that the Mahdist State of Sudan is most notable.
Such is evident during the Mahdi's lifetime, when he wrote letters to other Muslim leaders asking them to accept him as Mahdi: Muhammad Yusuf, Sultan of Wadai; Muhammad al-Sanusi, head of the Sanusi order in Libya; Hayatin b. Sa`id, grandson of Uthman don Fodio, founder of the Sokoto Caliphate in what is now Nigeria.
Despite the fact that only the last allegedly accepted his Mahdiyah, such communiques are clear evidence of the Pan-Islamic (or at least Pan-African Muslim) aspirations of Muhammad Ahmad. No doubt his Pan-Islamic vision had been passed on to his followers for "the Ansar expected a long series of victories which would make the Mahdi master of the Islamic world.
The news of his death [thus] came as a terrible shock…." After Muhammad Ahmad's death the ruling caliph `Abd Allah tried to continue with the Mahdist expansion via jihad. One of the main targets was the neighboring Christian kingdom of Ethiopia, which the Mahdists often invaded but could never subjugate. Mahdist forces also tried to incorporate, via jihad, territories to the south and west of Sudan, with little success.
The Mahdist caliph also tried several campaigns against what was by then British Egypt (the British having occupied the country in 1881, in the wake of the `Urabi Pasha uprising and in order to safeguard the Suez Canal). All of these failed miserably and in fact the total annihilation of a large Mahdist force in southern Egypt in 1889 effectively ended the expansionist phase of Sudanese Mahdism.
As for `Abd Allah's ideology, "the strength of his [`Abd Allah's] Mahdism made it impossible for him to compromise with the 'infidel' rulers of Egypt…and accept recognition as a mere Sudanse sultan under a protectorate.