IT IS with the deepest regret that we have learned of the death of Emperor Haile Selassie. For five decades, he was a towering leader not only of his own country but of the entire African Continent. At the time of the invasion of his country, he was an inspiration to everyone around the world who believes in national independence and peace with freedom among nations. As a friend of this country and as a symbol of the emergence of developing nations, he will be greatly missed. But his achievements--peaceful cooperation among African States and between African States and the rest of the world--will live on and continue to have fullest American support.