The tiny Mediterranean country, already deep in economic and political crisis, has been without a president for more than two years amid bitter divisions between Shiite Muslim group Hezbollah and its opponents.
Israel dealt Hezbollah's armed wing a serious blow during a two-month war this autumn and killed the group's influential leader Hassan Nasrallah.
The Iran-backed group, accused by critics of blocking a parliamentary majority in a dozen previous bids to elect a new head of state, has also lost a key ally in neighbouring Syria since Islamist-led forces toppled president Bashar al-Assad last month.
But analysts say there was no indication that the 13th presidential vote planned for later this week will be any more productive.
"The Lebanese people still have no idea whether it will lead to the election of a president or whether it will end in failure," said Lebanese analyst Karim Bitar.
Under multi-confessional Lebanon's power-sharing system, the president must be a Maronite Christian.
In a country rocked by a civil war from 1975 to 1990, the deeply divided ruling class usually agrees on a name, but leaders have been unable to reach consensus since the term of the last president, Michel Aoun, ended in October 2022.
Bitar said a leading candidate in Thursday's vote is army chief Joseph Aoun, "who seems to be supported by the United States and to a lesser extent by France and Saudi Arabia".
But "there is still some reluctance among certain political parties... to elect him," said the analyst.
'Distrust'
Visiting US envoy Amos Hochstein on Monday urged the ruling class to take advantage of the fragile truce between Israel and Hezbollah and reach "political consensus".
Bitar said that "often, it is at the very last minute that regional and international superpowers indicate their preference and put pressure on MPs who simply follow" suit.
Former president Michel Aoun -- who is not related to Joseph Aoun -- was elected in 2016 after a deal between Hezbollah and its opponents ended a two-and-half-year deadlock during which the position was also vacant.
"Hezbollah today is no longer capable of imposing someone really close to its camp after the fall of the Syrian regime and after the weakening of Hezbollah during the war," Bitar said.
But "it can still oppose someone that they really distrust".
Hezbollah and its allies have backed former minister Sleiman Frangieh, who is a friend of Assad.
But, according to David Wood, Lebanon analyst at the International Crisis Group think tank, "Frangieh's chances have nosedived in recent weeks due to the severe weakening of Hezbollah and the downfall of Bashar al-Assad, his key political backers."
Hezbollah and its ally Amal movement, led by Lebanon's powerful parliament speaker, 86-year-old Nabih Berri, were "considering other options behind the scenes", said Wood.
'Serious obstacles'
Other names circulating include the leaders of Lebanon's two main Christian parties, Michel Aoun's son-in-law Gebran Bassil, and staunch Hezbollah opponent Samir Geagea.
Former finance minister and International Monetary Fund official Jihad Azour, acting security chief Elias Baissari, and two lawmakers -- Nehmat Afram and Ibrahim Kanaan -- are also possible contenders.
Candidates do not need to declare themselves to be in the race.
Wood said 60-year-old Joseph Aoun still needed "to overcome some serious obstacles" to be elected, including lack of support from the top Christian parties.
The Free Patriotic Movement, led by Bassil, "outright opposes Aoun's nomination," said Wood.
And Geagea's Lebanese Forces have not declared their support.
On top of this, "it remains unclear how Lebanon's fragmented Sunni blocs will vote", Wood added.
Aoun would need a two-third majority -- at least 86 out of 128 lawmakers -- to be elected president.
If he or any other candidate fail to garner that many votes, parliament will hold a second round, where a simple 65-vote majority is needed to win.
The constitution stipulates that presidential candidates should not have held high public office for the past two years, which would technically disqualify Aoun.
Parliament speaker Berri, however, has been reported as saying he opposes any constitutional amendment.
If elected, Aoun would be Lebanon's fifth army commander made president, and the fourth in a row.
Like presidents, military chiefs too are by convention Maronites.
