[CMS]

I’d simply go with...His Excellency Field Marshal Supreme Potentate for Life

[Cecily]

Here’s a better one:

His Excellency, President for Life, Field Marshal Al Hadji Doctor Idi Amin Dada, VC, DSO, MC, Lord of All the Beasts of the Earth and Fishes of the Seas and Conqueror of the British Empire in Africa in General and Uganda in Particular.