Lebanon is inching closer to the possibility of a constitutional vacuum as rival political camps remain at loggerheads over who should replace pro-Syrian president Emile Lahoud, whose presidential term ends on Friday.

According to AFP, Lebanon's parliament speaker postponed a vote by MPs to elect a new president until Friday. Three previous sessions to elect a successor to Lahoud have already been postponed amid fears that failure to reach an agreement could deepen a year-long political crisis and result in two governments -- one opposed to Syria and another backed by Damascus; a grim reminder of the end of Lebanon's 1975-1990 civil war when two competing administrations battled it out.

In 2004, parliament amended the constitution to extend the 6-year-long mandate of President Emile Lahoud for three years. At the time, Syria was a political power-broker in Lebanon, where it had more than 10,000 troops.

But the extension of Lahoud’s presidential term turned out to be the start of Lebanon’s worst political crisis since the civil war. Since 2004, there have been eight assassinations of top anti-Syrian figures, including former prime minister Rafiq Hariri, whose killing was followed by a withdrawal of Syrian troops from Lebanon and a devastating war between the resistance group Hezbollah and Israel.

Today, the situation is as follows: The anti-Syrian camp has a majority in parliament for the first time in decades and wants to use it to install someone from its coalition as president.  

On the other hand, the pro-Syrian opposition accuses the Western-backed ruling majority of doing the U.S.’s bidding in Lebanon and refuses to accept a president chosen by Washington, insisting on a compromise candidate. 

If the parliament failed to elect a president by Friday, Prime Minister Fouad Siniora, an ally of the West, would take over executive power under the constitution.

But the opposition has already warned it will not recognise Siniora's powers and there are fears it might form a rival cabinet.

On Monday, Mohammed Raad, leader of Hezbollah's parliamentary bloc, warned of a "catastrophic picture" in Lebanon without a deal between the opposition and the governing coalition.

"Who then rules the country?" he asked. “Constitutional life would be gone with the wind," he told the group's al-Manar TV.

The parliamentary majority has also threatened to elect a president by a simple majority vote in the assembly, instead of the required two thirds - a move the opposition rejects as unconstitutional.

"The opposition has serious options to confront the unconstitutional steps which the loyalists will take," Raad said.

(See video: Nasrallah calls for transparent presidential polls)

• Battle for influence

It’s interesting that a lot of international attention is directed towards a small country like Lebanon, which has always been at the centre of a tug-of-war between world powers.

Although the president in Lebanon wields little power, the country’s presidential election was on the agenda of the U.S. Secretary of State Condoleezza Rice when she held talks with some of her European counterparts in Turkey on the sidelines of a recent summit on Iraq and its neighbours.

Lebanon’s political crisis was also discussed between the U.S. President George W Bush and French President Nicolas Sarkozy in Washington earlier this month.

French foreign minister Bernard Kouchner and Arab League chief Amr Musa are currently in Lebanon to help the various political leaders to reach a deal by Friday midnight deadline. 

The Russians have also weighed in with a call on Lebanese leaders to "realise the historic responsibility and reach accord" at this "fateful" moment for Lebanon.

According to an article on the BBC, the battle for influence over the Middle East isn’t just being fought in Iraq, but also in Lebanon. In fact, the election of a new Lebanese president is widely seen as an extension of the regional confrontation between the United States and Europe on one side, backing the parliamentary majority, and Iran and Syria on the other, supporting the Hezbollah-led opposition.

The whole region could be affected if Lebanon failed to elect a new president; an event that could create civil tensions in Beirut that would in turn spread to the entire Middle East.

Many observers, including some members of the anti-Syrian camp, support a compromise solution in the form of a consensus candidate to avoid creating tensions amid growing fears of a U.S. military strike against Iran.  

However, the anti-Syrian camp and their Western allies reject this solution on the ground that electing a compromise candidate would mean giving in to Hezbollah.

The U.S. fear of losing Lebanon to the Syria-Iran camp could be best illustrated in recent statements by Condoleezza Rice and the U.S. ambassador to the UN, Zalmay Khalilzad, who said that the governing coalition should choose the president.

Such interference led many opposition figures in Lebanon to protest, complaining that the Lebanese should resolve their problems on their own.