FACTBOX - The main players in Lebanon's crisis

(Reuters) - Rival Lebanese leaders are scheduled to hold talks in Qatar on Friday aimed at resolving 18 months of political conflict that has triggered bouts of lethal fighting, paralysed government and left the country without a president since November.

Following is some background on the main political leaders and parties involved the crisis in Lebanon:

RULING COALITION

- The March 14 coalition holds a majority of 68 seats in the 128-member parliament and backs the government of Prime Minister Fouad Siniora. The coalition is staunchly opposed to any Syrian influence in Lebanon and is backed firmly by the United States, France and regional power Saudi Arabia. Its key players are:

* Saad al-Hariri: The coalition leader is the Sunni Muslim son and political heir of assassinated former Prime Minister Rafik al-Hariri. He also holds Saudi citizenship.

* Walid Jumblatt: The leader of the Druze community and the Progressive Socialist Party (PSP). His party played a prominent role in the 1975-1990 civil war but he shifted his alliance with Syria in 2004 and has become a U.S. ally.

* Samir Geagea: The Maronite Christian leader of the Lebanese Forces, a civil war militia turned political party. He was released from 11 years of jail after Syrian forces left Lebanon in 2005 following a pardon over civil war murders.

OPPOSITION

-- The opposition, which holds 59 seats in parliament, is led by Hezbollah and demands full participation in the running of the country. Another parliamentary seat remains vacant since the September assassination of a member of the ruling coalition.