Over the past half-century or so, South Africa has earned the reputation as the economic powerhouse of Africa. While most of the continent has struggled to develop effective institutions and competitive industries, South Africa's unique geographic and historical advantages have enabled its economy to outshine the rest. Along with a handful of its neighbors that boast similar advantages, South Africa has leveraged its economic success to expand its reach north, gaining influence over large swaths of the continent. Today, geography continues to underpin South Africa's strength -- as well as its ambitions -- in spite of its many challenges ahead....