FACTBOX: Possible successors to Israel's Olmert

(Reuters) - Prime Minister Ehud Olmert's decision to quit after his party chooses a new leader in September could trigger early national elections in Israel, paving the way for any of several possible successors:

* TZIPI LIVNI. Foreign minister and chief negotiator with the Palestinians, Livni is seen as the likeliest successor from within Olmert's Kadima party. The most powerful woman in Israel since Prime Minister Golda Meir in the 1970s, Livni, 50, called on Olmert to quit last year after a scathing report on Israel's 2006 war in Lebanon. He didn't. Nor did she. Daughter of a prominent right-wing Zionist, she is a former intelligence agent. Like Olmert and former prime minister Ariel Sharon, she left the right-wing Likud party in 2005 to found Kadima.

* EHUD BARAK. Defense minister who leads the Labor party, Kadima's main coalition ally. Barak is not a member of parliament so he could not become prime minister without first winning a seat. A much-decorated commando, top general, and prime minister from 1999-2001, Barak, 66, has called for Kadima to choose a new leader. When he campaigned last year for the Labor leadership, he said Olmert should quit if an inquiry faulted him over the Lebanon war. This year, it did. But Barak said he would call for Olmert to go "at a more convenient time".

* BENJAMIN NETANYAHU. Prime minister from 1996-99 and leader of the opposition Likud party since Sharon, Olmert and others bolted to Kadima. Educated in the United States, he became a decorated commando. As finance minister under Sharon from 2003, Netanyahu, 58, pursued economic reforms that angered the left but are credited by many for economic growth. Tops many polls as likely winner if parliamentary election, not due until 2010, is called early.

* HAIM RAMON. A close Olmert confidant, Vice Premier Ramon quit the Labor party to join Kadima. He was forced briefly to resign his cabinet post following his conviction for indecent assault against a woman soldier but was allowed to return as a minister by an appeals court. He is one of the government's most active supporters of peace talks with the Palestinians.

* SHAUL MOFAZ. Transport minister and a former army chief and defense minister, Mofaz is known for his tough tactics in crushing a Palestinian uprising that erupted after peace talks failed in 2000. The Iranian-born military man has launched a campaign for the Kadima party leadership to replace Olmert.