The New York Times offers a good analysis of the connections between South African President Thabo Mbeki and his Zimbabwean counterpart, Robert Mugabe, and examines Mbeki's seemingly odd (or nonexistent) diplomacy:

"The world’s puzzlement with Mr. Mbeki’s approach — walking softly, carrying no stick — has turned into deep frustration these past two months as state-sponsored violence in Zimbabwe has become so sweeping
that the opposition’s candidate, Morgan Tsvangirai, who outpolled Mr. Mugabe in the first round, quit the race five days shy of the presidential runoff on Friday."

Photo from the World Economic Forum's Flickr page.