Lebanon is home to 18 religious sects, each with their own political factions. As part of the truce that ended Lebanon's Civil War, the 128 seats in parliament are split between Christians and Muslims. The even division is outdated; a mass of Christian have left Lebanon over the years, leaving a community that represents an estimated 35 percent of the population. It's now assumed that Christians, Sunnis and Shiites each make up roughly a third of the country, with top government positions structured so that no one group can take control.
Ahead of this weekend's race, Christian parties split their support between the two rival camps -- some joining forces with the Sunni-led government, others with an opposition led by Shiite Hezbollah. Sunday's outcome depends on which Christians parties get the most votes in key electoral districts.
The head of Lebanon's largest Christian bloc, Michel Aoun, formed an alliance with Hezbollah three years ago that widened base for Sunday's showdown. Since then, other sects have joined the opposition, from Armenian Christians to factions within the Sunni and Druze communities.
Aoun himself is running on the Hezbollah coalition's platform of "change and reform," bolstered by strong personal appeal. A revered Civil War general known for fighting Syrian presence in Lebanon, his partnership with Syrian-backed Hezbollah was a political about-face. Some accuse him of selling out to gain power; others credit him for protecting Christians through a strategic alliance with Lebanon's most powerful force.
On the other side, allied with the March 14 camp, a collection of Christian parties are worried about the rise of Hezbollah and its Syrian partners. On Saturday, the Christian community's highest religious voice, Maronite Patriarch Nasrallah Sfeir, took a rare partisan stance, reportedly warning that the "Lebanese entity and its Arab identity" were at stake, and that voters should resist attempts to "change the face of Lebanon."
Shiite Hezbollah, founded with the goal of a militarized Islamic state in Lebanon, says that is no longer their aim; they now emphasize governing by consensus, with their broad base of sectarian allies.
Hezbollah has offered its rivals veto power in its government, in the event its coalition wins on Sunday. Oussama Safa, head of the Lebanese Center for Policy Studies, says the offer is a calculated act of diplomacy.
"Otherwise Hezbollah will be seen as capturing the state, which it wants to avoid at all costs," he said.
Even among its partners, however, one issue is not up for discussion: Hezbollah's weapons and military assets. With a separate security infrastructure, Hezbollah has effectively created a "state within a state" -- only theirs is more efficient and far bolder, constantly challenging Israel and verbally committed to fighting another war with Lebanon's neighbor to the south.
The recent capture of an alleged ring of Israeli spies, operating in Lebanon with high-level security access, has been a fresh talking point in Hezbollah's security arguments.
That defiance of Israel is a mainstay of Hezbollah's Iranian ties.