EditorUN Secretaries General Trygve Lie, Dag Hammerskjold, U Thant, Kurt Waldheim, Janvier Perez de Cuellar, Boutros Boutros Ghali, Kofi Annan – and now Ban Ki-Moon – all had a difficult file on Congo, with each of them passing it on to their successor as a pending file, and all except Dag Hammerskjold paid very little more than lip service to resolve Congo’s vast quagmire. Yet none ever admitted failure.Today the file gets bigger, not smaller. My wishes to Secretary General Ki-Moon. Can’t envy you.(Reaction to an opinion titled, The Heart of Darkness, published on Tuesday, August 28)Gregg, New York