FACTBOX: Scenarios for scandal-hit Israeli PM Olmert

(Reuters) - Defense Minister Ehud Barak called on Wednesday on Ehud Olmert to step aside as Israel's prime minister or face the collapse of his coalition and an early election after damaging testimony in a corruption case.

Following are some possible scenarios for what might happen next:

* Olmert has survived previous calls for his resignation, including from Barak, leader of his main coalition partner Labor. Although Barak's latest call is much more direct and unconditional than previous criticisms, Olmert could still try to weather this storm by staying in his job and arguing he will only resign if he is indicted in the corruption case. He could, however, be forced from office after a parliamentary election.

* Olmert could bow to pressure and take a leave of absence, temporarily handing power to his deputy, Foreign Minister Tzipi Livni, for up to 100 days. Analysts say he may be reluctant to hand over to someone he sees as a major rival within his centrist Kadima party and the cabinet. However, Olmert and Livni are the two Israeli leaders most involved in U.S.-sponsored peace negotiations with the Palestinians and so a Livni government is seen by many analysts as offering the most continuity for the process if Olmert were to go.

* Olmert's centrist Kadima party has no mechanism by which to unseat him as leader. But if Barak pulls out of the coalition government it could trigger a parliamentary no confidence vote that would bring down the government and give President Shimon Peres a chance to appoint a new prime minister. If, however, he felt no one could form a stable coalition, he could choose to ask parliament to dissolve itself and hold an election.

* If Olmert did resign outright, Peres could also simply name a replacement after consultation with leaders of parliamentary parties. The likely frontrunner would again be Livni, although unlike in the case of Olmert stepping aside temporarily in favor of his deputy, her appointment would be less certain. Barak is not a member of parliament and cannot therefore be prime minister without first winning a seat.

* If the present coalition breaks up, Peres could turn to a leader willing to forge a different line-up of alliances among the 12 groups in parliament. Of 120 seats, Kadima has 29, Labor 19 and the right-wing opposition Likud 12. However, if no leader could secure a parliamentary majority an election would follow. The next scheduled election is not until 2010.

* An election must be held within five months of the Knesset voting to dissolve itself. In practice, that gap is shorter. Polls show Likud would emerge strongest if a vote were held now.

* Any of the above outcomes could disrupt U.S.-backed peace talks with the Palestinians, which Olmert and President Mahmoud Abbas started in November, as well as recently-announced indirect negotiations with Syria.

(Jerusalem Newsroom)