Ehud Barak wants to be defense minister. When he served as defense minister, he was mainly prime minister and not-so-much defense minister. He did not take the job seriously, leaving then chief of staff Shaul Mofaz, who complained to him of his woes, to do as he wished. But now Barak is ready to take on the Defense Ministry and look after it, as if it were the most precious thing in the entire world.

His CV, on paper, would impress any casting director: both Military Intelligence chief and chief of staff (until 12 years ago), both a little bit foreign minister and a little bit prime minister. In theory, he's a perfect candidate. In fact, he's a problematic one, who is inferior to the other candidate brandishing his security background, Ami Ayalon.

In a month, six years after the premiership and defense portfolio were taken from him, Barak will turn 65. He is familiar with all the precedents and eager to reenact them in fast replay. Yitzhak Rabin had to leave the prime minister's seat at 55, climbed back to the Defense Ministry at 62 and returned to the Prime Minister's Office at 70. Ariel Sharon was 55 when he was ousted from the Defense Ministry. At 72, he won the premiership, courtesy of Barak. And there was Barak's first idol, Moshe Dayan, who lost the defense portfolio at 59 and never quite recovered, not even when he served Menachem Begin as foreign minister.

Barak is waiting in the wings, in anticipation of the Winograd Committee's report. This may well bring down the entire defense leadership. But he will have difficulty presenting himself as the new broom to sweep away the debris left by the Winograd Committee, for Barak is a graduate from a previous inquiry. The Or Commission found his performance as prime minister in October 2000 faulty, inter alia, because he did not take sufficient action to prevent or restrict police use of fatal measures and did not do enough to calm spirits and events. "He did not fulfill his obligation to obtain as soon as possible the required information for making decisions and giving rational instructions," the commission said.

Ayalon is less experienced than Barak, but also has had fewer failures. As a major general in the General Staff (as head of the Israel Navy), he was one of the first who detected the gravity of the Palestinian terror threat. As head of the Shin Bet security service after Rabin's murder, he did not pretend to be an intelligence expert, but managed to rehabilitate the leadership of the disheartened organization in its crisis. He was a courageous Shin Bet chief, who faced the impetuous prime minister Benjamin Netanyahu, without a personal ax to grind. He has a passionate temperament, a tendency to concentrate on himself and positions that may be influenced, but Labor's stumbling team has no one better at the moment.

Barak, too, has a place on the team, but not as its leader, for two crucial and interrelated reasons. The first is corruption. This will be the super issue of Israeli politics in the years to come, and Barak is not the man to lead the campaign against it. One can assume there will be no peace process, and that an attack on Iran - if there is one - would derive from an essential national and military imperative, one that would be valid no matter who was in government. Here, too, Barak's advantages do not outweigh his disadvantages.

The central issue, immersed in the miasma of public disgust, is going to be the integrity of those in power. The leader of Labor must work against Ehud Olmert, not for him. Barak has not spoken out to criticize Olmert at all, not to mention the hints of corruption and scandals, and if he did so, he would sound sanctimonious. Ayalon could lead an anti-corruption campaign convincingly.

Barak chose not to be a Knesset member; he was loath to take a back bench in his party's faction. Therefore, he is now qualified at most to be a minister. Barak's leadership would condemn Labor to a second-fiddle role in the government. When the ground collapses under Kadima from the weight of the investigations around Olmert, Labor will be desperate for a leader capable of forming a government in this Knesset's term. Ayalon can do it; Barak cannot.