ONE FORGETS that a dozen years ago, when Robert McNamara became president of the World Bank development was widely considered a respectable but somewhat tame and peripheral cause, and the bank was regarded as a respectable but modest American-directed institution that invested chiefly in "safe" infrastructure projects like dams. To Lyndon Johnson it seemed a reasonable place to park a burned-out secretary of defense. At the World Bank, which was not consulted, Mr. McNamara's appointment was received with some chagrin.

Mr. McNamara's announcement that he will resign in a year, on his 65th birthday, finds both development and the bank in a very different place. Development is no longer simply a rich country's "cause": it has become an increasingly urgent issue defining the way nations relate to each other, the very shape of the world. The World Bank, meanwhile, has become the central institution transferring resources from rich to poor. It has grown in the volume of its loans, in the reach of the development goals it pursues -- these include not just economic growth but the distribution of services within countries and the amelioration of mass poverty -- and in its technical capacities. Mr. McNamara has directed this growth with relentless efficiency and evangelical fervor. Through his leadership, the free-enterprise system has been made relevant to the global poor -- an immense achievement crowned in a sense by China's recent decision to join "McNamara's bank."

Mr. McNamara's very success in making the bank critical to the Third World and in drawing others into financing development aid has transformed the politics of appointing a successor. His success denies the United States the discretion that Lyndon Johnson enjoyed when he named Mr. McNamara: the position is now being filled in the international spotlight. We hope he will be replaced by an American. This would afford a better chance that the American interest in the bank and its work would be understood abroad, and it would help ensure that American involvement, on which the involvement of others hinges, remains high.

For this to happen, however, the White House -- the nomination could be made at any time in the next year -- will have to offer a nominee of recognized high stature. Ideas and fashions change in development as in other fields. Mr. McNamara's expansion activities and loan policies need to have a close eye kept on them. But any bank president must have the savvy to deal with 130-odd member governments, the solidity to keep the confidence of the financial community and the compassion to win the cooperation of the poor. If the United States cannot nominate someone who promises to fill this bill well, other industrialized countries, and conceivably even developing countries, will. Mr. McNamara has set the standard by which his successor's appointment will be judged.