Until Saturday night, the government of Israel was dominated by the last two political descendants of Israel's first leader, David Ben-Gurion. With the assassination of Prime Minster Yitzhak Rabin, the number has been reduced to one -- Shimon Peres.
Mr. Peres has become prime minister of Israel for the second time, but there could be no satisfaction at having returned to that post through national tragedy. Mr. Peres is 72, one year younger than Mr. Rabin and after decades of being rivals, the two men had apparently become full, trusting partners.
They had made peace with each other, and then they made far more progress than any of their predecessors in making genuine peace with Palestinians and neighboring Arab states.
In 1994, they shared the Nobel Peace Prize with Yasser Arafat of the Palestine Liberation Organization, in recognition of the progress the three leaders made toward ending generations of armed conflict.
"You see," Mr. Rabin said after embracing Mr. Peres, a few minutes before an Israeli shot Mr. Rabin to death. "Things change not only in the world but also in the Middle East -- also for us."
And Mr. Peres mourned Mr. Rabin's death as the loss of "a friend, a partner, a leader."
They had needed each other for peace. Mr. Rabin probably could not have negotiated agreements with the PLO and Jordan without Mr. Peres' skills as a diplomat and his willingness to take risks. Mr. Peres could not have sold the accords to Israelis without the reservoir of public trust for Mr. Rabin.
Now, Mr. Peres leads a government assembled by his colleague but in which Mr. Peres was the only member Mr. Rabin had seemed to regard as a true peer. They usually met privately before the Sunday Cabinet sessions, and even then the full meeting was often a dialogue between only those two.
"The rest of us feel like children at the dinner table -- allowed to venture an opinion every so often but expected to listen respectfully while our elders discuss things," a Cabinet minister said last year. "And they speak in a language -- mutual experiences, a depth of understanding, a personal involvement in half a century of history -- that the rest of us don't have."
Their public careers have been vastly different but intertwined. Mr. Rabin -- dour, gruff, rarely eloquent -- was above all a military man: As a young army officer, he played important roles during Israel's war of independence in 1948 and was responsible for much of the planning behind the country's startling successes in the fighting in 1967, when Israel defeated Egypt, Jordan and Syria in six days of battles.
Mr. Peres seemed to be Mr. Rabin's opposite. Where Mr. Rabin was simple and direct, Mr. Peres was loquacious, often to his own detriment. He is a gifted tactician in politics but until the early 1990s was burdened with a reputation as a dreamer and a schemer.
An account of Mr. Peres' early years could be mistaken for a textbook on Zionist pioneers. Born in Poland in 1923, he was brought to Palestine by his parents when he was 11. During high school, he joined the Haganah, one of the underground Jewish self-defense forces. He worked as a shepherd. While still a teen-ager, he became one of the founders of a kibbutz.
And then the 1948 war intervened. He had already come to the attention of Mr. Ben-Gurion, who quickly drafted Mr. Peres to Haganah headquarters to oversee arms purchases and manpower. Mr. Peres would help transform it into Israel's Ministry of Defense.
He became the architect of the country's weapons industry. One of his inspirations was to initiate secret contacts with France for help in nuclear research, a program that would help Israel develop nuclear weapons. And most of this work was done before he reached age 30.
He was the country's leading technocrat, and Mr. Ben-Gurion eased his protege's way into the Knesset, Israel's parliament.
Mr. Peres continued his rise under a succession of Labor prime ministers, and in 1974, he became minister of defense. When Prime Minister Golda Meir resigned later that year, Mr. Peres sought to replace her as head of the Labor Party. His only serious competitor was Mr. Rabin, and therein lay the beginning of a rivalry that would last nearly 20 years.
Mr. Rabin won the contest to become prime minister, at Mr. Peres' expense, but a scandal would force Mr. Rabin to resign in 1977. By the standards of today, it was a scandal over almost nothing: Israel's press disclosed that Mr. Rabin's wife had a bank account in the United States, in violation of an Israeli law prohibiting bank deposits abroad.
Mr. Rabin's supporters suspected that allies of Mr. Peres leaked the information about the overseas account. Mr. Peres denied the accusation, but the damage was done. Until 1992, when Mr. Rabin was elected prime minister and chose Mr. Peres as foreign minister, they were simultaneously the two natural leaders of the left-of-center Labor Party and each other's greatest rival.
Mr. Peres ran for prime minister four times and lost three times, and even the one victory was less than complete.
As prime minister from 1984 to 1986, he had to share power with the main opposition party, the rightist Likud. He nevertheless managed to pull Israeli troops back from Lebanon and rescue Israel's economy from disastrous inflation. But in subsequent elections, he led his party to defeat.
He was replaced as party leader in 1992 -- by Mr. Rabin, who later that year was elected prime minister and named Mr. Peres foreign minister. And they together planted the seeds of the peace process.
Mr. Peres was relegated to the supervision of "multilateral negotiations" -- seminars and conferences that had not amounted to much and were expected to go nowhere. But he took the assignment without protest and plunged into the work.
"He's a politician's politician," said one associate. "He believes there's no situation you can't turn to your advantage if you work on it long enough. He looked around, and said, 'OK, if that's what they gave me to do, I'll build on it.' "
From there came the first productive contacts between Israel and the PLO in Oslo, Norway. And from there -- after many twists and turns -- the peace accord signed at the White House in 1993.
Now, Mr. Peres faces a situation as least as difficult, at least as seemingly impossible to resolve. An Israeli has confessed to killing Mr. Rabin. It falls to Mr. Peres both to rescue the peace process and rescue his country from itself.
"We accompany a great friend, a great leader, a great Jew, a great fighter, a man who pursued peace and achieved it, a man who brought peace to new heights," Mr. Peres said after Mr. Rabin's death.
"What can I say other than the need to be together, to be serious and to be loyal to the path. That is the thing he left behind."
Robert Ruby is The Sun's deputy foreign editor and was its correspondent in the Middle East from 1987 to 1992.