LONDON — "I am proud to be a citizen of a country where the prime minister can be investigated like an ordinary citizen," said Ehud Olmert on July 30, announcing that he would resign as prime minister in September to defend himself against corruption allegations. He should be even prouder: Three of Israel's last four prime ministers were under investigation for corruption when they left office.

To be fair, it was a stroke, not the corruption charges he was facing, that finally drove Ariel Sharon from office, and Benjamin Netanyahu subsequently beat the charges against him after being forced out as prime minister. Politics in Israel is a blood sport, and only the strong survive. Not one of the country's last five prime ministers has managed to serve out a full term of office.

What happens next is hard to predict. Tzipi Livni, the foreign minister, and Shaul Mofaz, former army chief of staff and now transportation minister, are the leading candidates to succeed Olmert as leader of the Kadima party.