By Tina Rosenberg

New York Times

Every year at this time, a private organization called Transparency International ranks countries on how corrupt they are perceived to be. The current index is notable for what has not changed: the sad persistence of sub-Saharan Africa at the bottom of the heap.

What is new this year is that Transparency International has new company in fighting corruption. A Sudanese cellphone billionaire named Mo Ibrahim announced recently that he will give an annual prize worth more than $5 million to an African head of state who was freely elected, turned over power to a freely elected successor and governed well while in office. Skeptics might ask how the cause of fighting corruption will be served by awarding what will be the world's largest individual prize to a powerful leader for doing his job. The answer can be found in the dreary immutability of Transparency's list.

Political leaders talk about fighting corruption because voters care about it. They also like to prosecute corrupt past officials because it is showy and those officials tend to be adversaries, though this does very little to fight present graft. But leaders have a bad record of doing what really works: open government to public scrutiny, carry out bidding for government contracts transparently on the Internet, pay government officials decently, investigate public officials who buy Mercedeses, cut red tape and restructure government offices to remove opportunities for bribery.

Corruption is tamed when government agencies are set up to make corrupt behavior difficult. But many government agencies in poor countries cut costs by paying workers a pittance or even nothing, expecting them to live off bribes. Corruption benefits leaders personally. It rewards supporters and greases the political machinery. And anyone who really tries to fight corruption makes a host of inconvenient and perhaps dangerous enemies.

That's where Ibrahim's prize comes in. In most countries in Africa, leaders today have unlimited opportunities to plunder and no checks on their power. But once they leave office, they lose everything. With rare exceptions, they receive no further salary or perks. This is a perfect system for encouraging presidents to steal as much as they can and cling to office. The Ibrahim prize seeks to help change this equation. A panel of experts in African governance will choose a former president to get $5 million over 10 years, and $200,000 per year for life after that. The ex- president will also receive $200,000 a year to give to charity. (The prize may not be awarded every year.)

The prize increases the appeal of leaving office, and helps presidents feel less need to pilfer their way into a comfortable retirement. It will also give them an incentive to improve the lot of their people. Its limitation is that it mainly affects the behavior of the chief executive. Addressing big-fish corruption is not a full solution. Even a puritanical leader can run a very corrupt government, especially if he suffers from the misimpression that his own probity is enough.

What counts is how the system is structured. To change that, Africa, like elsewhere, needs more than an Ibrahim prize. It needs a permanent source of political pressure from citizens and business groups - not just general disgust, but advocacy for specific reforms. Corruption always carries its own powerful lobby. Honest government needs one as well.