"Through Hezbollah in Lebanon and Hamas in Gaza, Iran has arrived at the shores of the Mediterranean," said Soueid, the candidate with the ruling March 14 movement. Hezbollah's opponents also fear an opposition win could destabilize Lebanon's economy, discouraging investment from traditional backers in the Gulf and the West.
Hezbollah's allies see Soueid's concerns as fear-mongering, an effort to scare swing voters out of backing its allies.
"The country will stay as is, and nothing will change [if the opposition wins]. Nothing will change at all in terms of Lebanon's external relations," said Alain Aoun, a Christian candidate with the opposition and nephew of party leader Michel Aoun.
While the two sides paint different visions of what Lebanon could be after today's vote, a third perspective says that even if its coalition gains power, Hezbollah won't want to take center stage.
"They control the system better in a position where they are sort of behind the curtain," said Michael Young, a leading analyst in Beirut. "If they are in front of the curtain, they take the blame for the problems."
With or without a Hezbollah win, the security equation between Israel and Lebanon could change with progressive diplomacy between the U.S. and Iran.
"If the U.S. is talking to Iran, then Hezbollah is on the table," said Safa, the policy analyst. "[America] is not so naïve to think they can embark on a Middle East peace process without dealing with non-state actors such as Hamas and Hezbollah. They will have to deal with them indirectly."
With few independent polls in Lebanon, it is notoriously difficult to tell who will come out ahead. The Eurasia Group, a U.S.-based political consultancy, predicts a narrow win for March 14, the ruling pro-Western camp.
The uncertainty and potential instability of this election are a condition of Lebanon's fractured politics. They're part of a norm that Lebanese voters have learned to live with, says Marny Issa, 35, who sells political paraphernalia at his gift shop north of Beirut.
"If these issues were to be resolved and all of us were united, Lebanon would no longer be Lebanon."