Reasons Why Katanga Secession Failed.

Opposition from elites, parliamentarians and ministers. The news of Katanga secession wasn't welcome by the Congolese elites who immediately decampaigned it.
 
Government's determination to preserve unity. Inspite of the power struggle between Kasavubu and Lumumba, the central government took a firm stand by opposing and fighting the secessionists.
 
The role of Lumumba helped to weaken the separatists. Right from the pre- independence period, the supported Unitarians and when Tshombe declared a secession, he vehemently broadcasted against it.
 
The assassination of Lumumba on 17"' January 1961 by Moise Tshombe caused a lot of resentment within Congo and from the international community.
 
Opposition from the Catholic Church.
 
Lack of popular support from Katanga. Not all the tribes of Katanga supported Tshombe.
 
The role of the Casablanca group. They condemned the UN's lukewarm attitude and even threatened to withdraw their troops from the UN command in Congo.
 
The role and death of Dag Hammarskjold who like Lumumba, was looked at as a Martyr who had died at the altar of Tshombe's secessionism.
 
Support from the Soviet Union.
 
The withdraw of Belgian troops. After killing Lumumba, Tshombe was no longer a favourite of the Belgians.
 
The re-organisation of the Congolese army under Mobutu led to the failure of the secession.
 
On the other hand, Katanga's army was disorganized after the departure of the Belgians; it also suffered an arms embargo imposed by the UN.
 
The formation of the OAU in May 1963 led to the failure of the secession.
 
The flight of Tshombe to USA demoralized his soldiers and led to the collapse of the secession.
 
The 1963 Afro-Asian and Arab conference condemned the secession.
 
The efforts of Cyrilla Adoula helped to weaken the secession. He was the new acting premier who held talks with Tshombe at Kitona leading to the Kitona agreement in which Tshombe temporarily called off the secession.
 
The promulgation of a new constitution in April 1964 helped to water down the secession.
 
The formation of a government of national unity. This was in July 1961 with Tshombe as Prime Minister.

National Movements and New States in Africa