Malaysian Prime Minister Mahathir Mohamad has announced that he plans to step down. It is difficult to envision that country without Mr. Mahathir at the helm: He provided Malaysia with its energy, its backbone and its vision. His pride and sharp tongue also made him a lightning rod for criticism, but few men have played a more important role in pushing a nation into modernity. Mr. Mahathir's remaining task is ensuring that the succession is a success. Most significantly, that means institutionalizing politics so that the nation is not dependent on any individual. Mr. Mahathir must assume that Malaysia will never have another leader like him; that is a safe bet.

Mr. Mahathir's resignation was only a matter of time. He is 76 years old, one of Asia's longest-serving leaders, and has a heart condition. He has courted controversy for much of his tenure; he has been dogged by accusations of anti-Semitism and has made no bones about blaming outsiders for his troubles. The prime minister first mooted the idea of stepping down in 1995. He chose a successor, Mr. Anwar Ibrahim, but the two men split in 1998 in the wake of the Asian economic crisis. Mr. Anwar was then charged with sodomy and abuse of power and was jailed.

Some claim that the real problem was Mr. Anwar's popularity, which threatened to rival that of the prime minister. The bigger issue was their different perspectives on ways to respond to the economic crisis. Mr. Anwar favored the conventional solution -- continuing liberalization and more Western-oriented remedies. Mr. Mahathir spurned prevailing opinion and opted for capital controls. That won him international condemnation, but it preserved Malaysia's independence in economic decision-making, the foundation of Mr. Mahathir's economic legacy. Most important, Mr. Mahathir's decisions helped Malaysia weather the crisis, which only solidified his reputation and legacy.