I have never made a secret of my distaste for Muhammadu Buhari – ‘the least awful option’, according to the Economist – and I am not doing so now that he has been declared winner of the presidential election in Nigeria. One of the more notorious dictators during the long years of the military, he now claims to be a born-again democrat. Perhaps so. All will be revealed after he moves into Aso Rock on 29 May, with the proviso that he will be obliged to work within the terms of a constitution he cannot abrogate by decree.