(Adds quotes from Gemayel, details)
By Nadim Ladki
BEIRUT, Aug 6 (Reuters) - Lebanon's Christians emerged on Monday from a by-election split down the middle after opposition leader Michel Aoun's candidate narrowly beat former President Amin Gemayel, a pillar of the Western-backed government.
Both sides took comfort from Sunday's contest in the Metn area north of Beirut, but the outcome offered no clear pointers to the forthcoming presidential election or a way out of a 9-month-old deadlock paralysing Lebanon's ruling institutions.
"It does not close the house of Gemayel or deliver Aoun to the presidency," political analyst Samir Constantine said.
Aoun is the only declared candidate for president, always a Maronite Christian under the sectarian power-sharing system.
Choosing a successor to pro-Syrian President Emile Lahoud is the next political battle for the anti-Syrian forces behind Prime Minister Fouad Siniora and the opposition that groups Aoun with Hezbollah and Amal, Shi'ite factions backed by Damascus.
The ruling coalition's majority in parliament fell to 69 in the 128-seat assembly after the Metn election. A pro-government candidate easily won another by-election on Sunday.
"The Metn elections ended politically without a victor and a vanquished. There was a loser, but there was no winner," said former Prime Minister Selim al-Hoss, a Sunni elder statesman.
"If the contest was a contest of sizes, then both competitors were effectively down-sized."
Aoun's candidate, Camille Khoury, took the seat by 418 votes out of about 79,000 cast, but that margin undermined the former general's claim -- based on the results of parliamentary elections in 2005 -- to enjoy 70 percent Christian support.
"They just can't beat me," said Aoun after the result.
Gemayel, who contested a seat that fell vacant when his son Pierre was assassinated in November, said his strong showing gave him a mandate to continue his anti-Syrian path.
"The battle for sovereignty and independence is not over yet," he told a news conference.
He called on various Christian leaders to agree on a joint candidate for the presidency. "There should be an understanding on the presidential election as soon as possible."
Gemayel ran an emotional campaign in which he accused Aoun of seeking a return of Syrian tutelage.
But the dent in Aoun's popularity, perhaps due to Christian dismay at the accord he forged with Hezbollah in 2006, is small comfort for the defeat Gemayel suffered in his own backyard.
Gemayel leads the Phalange Party founded by his father Pierre in the 1930s. Its Maronite militia played a major role in Lebanon's 1975-90 civil war, but the party is now aligned with anti-Syrian Sunni, Druze and Christian factions led by the son of assassinated former Prime Minister Rafik al-Hariri.
The ruling coalition is supported by the United States, France and Saudi Arabia.
In a Sunni district of Beirut, a by-election for slain anti-Syrian lawmaker Walid Eido produced an easy win for a pro-government candidate who had no significant opposition.
Headlines in Lebanese newspapers reflected their partisan interpretations of the result in the Metn.
"Two-thirds of Maronites vote for Gemayel, their seat goes to Aoun by 418 votes," said the pro-government Al-Mustaqbal, contending that Armenian voters had swung the vote Aoun's way.
The pro-opposition As-Safir said: "The Metn democratically defeats Amin Gemayel and with him the 'majority'." The English-language Daily Star lamented the lack of campaign debate on policy issues and said it did nothing for reconciliation.
Gemayel and his allies accuse Syria of orchestrating the assassinations of Pierre Gemayel, Eido, Hariri and other anti-Syrian figures. Damascus denies any involvement.