As Colonial Office Assistant Undersecretary for African Affairs, Cohen was involved in negotiations for a federal state for the Rhodesias and Nyasaland in 1950.
However, he compromised his ideals to combat a threat that he perceived to be even more menacing: the risk that Southern Rhodesia, if it turned hostile, would fall into the orbit of the National Party government in South Africa.
Having come to terms with this compromise, Cohen went on to become one of the central architects and driving forces behind the creation of the Federation, often seemingly single-handedly untangling deadlocks and outright walkouts on the part of the respective parties.
His forced departure made the Kabaka an instant martyr in the eyes of the Baganda, whose latent separatism and anticolonial sentiments set off a storm of protest.
The Kabaka's new power was cloaked in the misleading claim that he would be only a "constitutional monarch," while in fact he was a leading player in deciding how Uganda would be governed, and would become the country's first president in 1962.
Cohen had argued against offering independence to the territory, and pro-independence Southern Cameroonians blamed him for the fact that the UN did not allow that question to be put.