Mission Impossible; Embattled: As he nears the end of his second term in June, Wolfensohn has to admit that his hope of reforming the World Bank is beyond reach.(James Wolfensohn)

Byline: Sebastian Mallaby (Mallaby is a Washington Post columnist and the author of "The World's Banker: A Story of Failed States, Financial Crises and the Wealth and Poverty of Nations.")

When James Wolfensohn landed the job of World Bank president in 1995, friends told him he was crazy. Wolfensohn was making millions running a Wall Street boutique, while hobnobbing with royalty and movie stars. Why take on the thankless responsibility of saving the world's poor? He did take it on, driven by a messianic mix of ego and idealism.

Ten years on, Wolfensohn's record at the World Bank is a case study in leadership at big public institutions. He launched himself into reforming the bank's managerial dysfunction, its failed theory of development and its unpopularity on the left and right. Famous for brilliance, ambition and temper, he changed the bank more than any other leader since Robert McNamara in the 1970s. His story shows what charismatic leadership can--and cannot--achieve.

Wolfensohn sought to shake up the snail-pace culture of the bank. When he got there, each loan went through a byzantine process with four color-coded stages, from white cover to yellow, green and gray cover, when it went to the board for approval some two years after conception. Wolfensohn delivered emotional speeches, trying to bring urgency to the bank's poverty-fighting mission. He sent hundreds of managers to Harvard Business School for a dose of private-sector thinking; he dispatched others to remote villages, hoping to revive idealism dulled by life inside a 10,000-person bureaucracy. He shook up a personnel system dominated by clannish national networks of French, Pakistanis and so on. He decentralized, pushing two thirds of the country directors out of Washington. But for all that, the cultural revolution never did materialize.

The reason is familiar to public-sector reformers, from Al Gore and his Reinventing Government program to William Bratton and his shake-up of the New York Police Department. A top CEO reports to a board of part-timers who meet perhaps a dozen ...