FACTBOX: Scenarios in Israel PM Olmert's legal troubles

(Reuters) - Israeli Prime Minister Ehud Olmert denied allegations of corruption on Thursday but said he would resign if indicted.

Following are some possible scenarios:

* Olmert has faced other investigations -- none of which has led to indictment -- and could weather this storm. However while the next election is not due until 2010, Olmert faces opposition, including within his own coalition, to steps he might take to make peace with the Palestinians. U.S. President George W. Bush wants a deal this year.

* Olmert has said he will quit if indicted, even though he is not obliged to do so by law. Another option could be for him to step aside temporarily for up to 100 days while his deputy, Tzipi Livni, took over.

* Olmert's centrist Kadima party has no mechanism by which to unseat him as leader. If he lost the confidence of his coalition cabinet, however, they could drive 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 Olmert did resign, Peres could name a replacement after consultation with leaders of parliamentary parties. The likely frontrunner is Livni, the foreign minister. Ehud Barak, defense minister and leader of Kadima's main coalition partner Labor, 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.

* 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.

(Writing by Avida Landau)