The appointment of a new chief of General Staff is always a reliable political barometer of the power balance within the cabinet. By law, it is the defense minister who decides on the new IDF commander and presents his candidacy for the government's approval. In practice, intense lobbying among the ministers precedes the decision, which is finally taken by the prime minister and defense minister, with the stronger politician of the two prevailing. In 1998, then-prime minister Binyamin Netanyahu was forced to accede to defense minister Yitzhak Mordechai's demand that Shaul Mofaz be chosen for the top job. "I just couldn't afford a crisis with Mordechai," the embattled Netanyahu admitted later to aides. Seven years later it was Mofaz, by this time a defense minister with no political base of his own, who was forced to accept the choice of his benefactor, prime minister Ariel Sharon, for chief of staff - Dan Halutz. What happens, though, when both prime minister and defense minister are politically weak? The general expectation until Tuesday night was that it would be Amir Peretz's successor who would make the decision. The defense minister is running fourth in the polls ahead of Labor's May 28 leadership primary, and he might not last in office even as long as that. It's not only Prime Minister Ehud Olmert who would dearly like to replace him as soon as possible; Peretz would be grateful for an easy way out of a job that has proved his political downfall. One of the ideas being considered by Olmert is holding a cabinet reshuffle next month. Although he wishes his confidant Haim Ramon all the best in his sexual harassment case, if the verdict, expected on January 31, blocks Ramon's way back to the Justice Ministry, Olmert could hand the job, currently held by Foreign Minister Tzipi Livni, to Interior Minister Roni Bar-On, opening up the possibility of Peretz moving to a new mega-ministry of interior and social affairs. The defense portfolio would then return to Kadima. Both Olmert and Peretz stand to gain a lot from such a scenario. Peretz would finally have a job commensurate to his experience and abilities, and he would have caused considerable damage to the prospects of his two main rivals for the Labor leadership, Ehud Barak and Ami Ayalon, both campaigning on the basis of their suitability to fill the post of defense minister. Olmert could then return the defense portfolio to Transportation Minister Shaul Mofaz, in the hope of mending their relationship, severely damaged after the prime minister took it away in the first place nine months ago. Olmert would hope to improve his public standing by having an experienced defense minister beside him and, temporarily at least, mollifying a potential Kadima rival. But for now, Peretz is still in office and though the timetable for appointing the new chief of General Staff is unclear, he and Olmert have made it quite clear that they plan to decide on a candidate very soon, ignoring calls to wait at least until the Winograd Commission investigating the Lebanon war delivers its interim report next month. Both men realize that a failure to reach a speedy decision would be yet another admission of their political weakness. To add credibility to their choice, they plan to hold consultations with senior politicians, including opposition leader Binyamin Netanyahu. However in separate statements, they have made it quite clear that the final word remains theirs. But can the two leaders, barely on speaking terms, reach a joint decision? And more crucially, what does Halutz's resignation mean for the two survivors of the troika that has been holding out together, in the face of intense public and political criticism, ever since the war ended? Despite the breakdown in Olmert-Peretz relations and the recurring tensions between Peretz and Halutz, the three men have refrained from attacking one another over their conduct during the war. Now that one side of the triangle has folded under the pressure, does that mean that the other two are about to topple? Halutz's resignation letter to Olmert was cordial and, other than his deliberate snub of Peretz - he only notified him of his plans two days after handing Olmert the letter - there are no signs that he plans to attack either of them once he's no longer in uniform. All three have yet to face questioning by the Winograd Commission and there's no telling what they might say behind closed doors. The commission's report might change everything, but in the meantime, Peretz will only leave the defense ministry if it's to his political advantage. Otherwise he'll hang around until the primary forces him out. And Olmert is not considering quitting. Halutz's departure might give a new and vigorous lease of life to the protest movement calling for their removal, but they are both battle-hardened and they have no plans to surrender. Over the next few days they will overcome their personal differences to appoint Halutz's successor, defiantly showing all their rivals that they're still standing.