SCENARIOS - After election, what next for Lebanon?

BEIRUT (Reuters) - A U.S.-backed alliance of Lebanese factions successfully defended its parliamentary majority in an election on Sunday, defeating an alliance including the Iranian- and Syrian-backed Hezbollah.

Led by Sunni politician Saad al-Hariri, the anti-Syrian "March 14" coalition won a majority in parliament, according to politicians in his alliance and the rival bloc. The new parliament convenes for the first time later this month.

According to Lebanon's sectarian power-sharing system, the parliament will elect a Shi'ite speaker. It is expected to extend the term of Hezbollah ally, Nabih Berri.

President Michel Suleiman, a Maronite Christian, will then consult lawmakers on their choice for the post of Sunni prime minister. He is obliged to go with the choice of the majority.

The prime minister-designate then holds consultations on the new government. Following are scenarios on how the new government may shape up:

HARIRI NOMINATED PM, REJECTS OPPOSITION VETO

Hariri, who has Saudi backing, is designated prime minister by a majority of legislators. Though not against the participation of Hezbollah and its allies in government, he refuses to meet their demand for effective veto power, setting the stage for political tension.

March 14's refusal to yield to the opposition's call for effective veto power in 2006 triggered a political crisis that last year pushed the country to the brink of civil war.

The U.S.-backed alliance finally agreed to the demand as part of a deal brokered by Arab mediators to end the worst civil strife since the 1975-90 war.

In an attempt to avoid a confrontation, Hariri might instead propose that President Suleiman be allowed to appoint a bloc of ministers with effective veto power, enhancing the head of state's role in government. Hezbollah and its allies, including Christian politician Michel Aoun, may not agree.

The dispute could drag on and a resolution would likely require the intervention of regional states.

HARIRI DECLINES PM NOMINATION

Hariri declines the nomination for prime minister, avoiding a potential confrontation with Hezbollah and its allies over the issue of veto power. He nominates an alternative candidate.

The alternative to Hariri may also propose a wider role for the president in the new cabinet, expanding the number of ministers that he appoints so the head of state effectively holds the balance of power in government.

One compromise solution could be a three-way split of government posts between Hariri's coalition, Hezbollah and its allies and the president.

PRESIDENT EMERGES MORE INFLUENTIAL

President Suleiman could emerge a winner from the election if negotiations over the new cabinet result in a greater say for him. Suleiman was elected head of state last year by parliament. He was seen as a candidate acceptable to both the rival sides at the time and supported by Saudi Arabia and Syria.

(Writing by Tom Perry; editing by Michael Roddy)