KENYA'S Supreme Court has blocked sweeping constitutional changes proposed by President Uhuru Kenyatta, the court said, declaring the process unconstitutional through a majority ruling. Kenyatta's political opponents said the failed changes were an attempt to widen the presidency's powers and has dominated early campaigning for an election in August. His estranged deputy and presidential candidate William Ruto has charged the changes would have led to an all-powerful presidency, while Kenyatta argued the proposal would promote power sharing among competing ethnic groups. In a majority judgement, the Supreme Court, whose ruling is final, upheld a finding by the lower courts that…