LONDON — Larry Summers was snatching lunch during the African Development Bank annual meeting while I interviewed him. Under no circumstances, his minder said, were we to take pictures while he was eating — a wise precaution as it spared our cameras from the backlash of presenting him chomping greedily on a huge burger.

It was a fascinating experience that said much about Summers, his voracious hunger, a man in a hurry, not thinking of all the consequences. Summers was then undersecretary for international affairs at the U.S. Treasury with a glittering career behind him, including entering MIT at 16, Harvard's youngest tenured professor at 28 and vice president for economics at the World Bank, and a still more glittering one ahead as U.S. treasury secretary, president of Harvard and, most recently, President Barack Obama's economic czar.

Summers' announcement that he will give up the leadership of Obama's economic team at yearend should give the U.S. president time to pause for thought about who should replace this brilliant, highly ambitious but deeply flawed man.