But as the Israeli offensive against Hamas in the Gaza Strip continues to rage, many are beginning to wonder what it would take for Hezbollah to open a new military front in order to distract Israel and ease the pressure on Hamas to the south.

For now, most Lebanese analysts and political leaders say that Hezbollah wouldn't risk its own domestic popularity ahead of critical May parliamentary elections it believes will solidify its power. Lebanese Information Minister Tarek Mitri told reporters Monday of a nationwide "sense of not wanting to be drawn into this" conflict.

"Expressing solidarity with Gaza," he said, "does not mean wanting to provoke an Israeli attack on Lebanon, or giving any pretext for that."

So far, Hezbollah leader Sheik Hassan Nasrallah has given no indication that his militia, armed with rockets from Iran and Syria replenished since its summer 2006 war with Israel, would launch or provoke a new conflict. A Hezbollah Cabinet minister even agreed last week to a Lebanese government statement pledging to keep the politically divided country from being drawn into the conflict.

But on Wednesday, Nasrallah did warn of dire consequences if Israel struck first.

"We are ready for any aggression," he told followers chanting "Death to Israel!" at annual Ashura religious ceremonies. "If you come to our villages, our lands, our neighborhoods, you Zionists will discover that the July [2006] war was nothing compared with what you'll face this time."

Almost all observers acknowledge that Hezbollah's reluctance to stage a military operation could change dramatically if the fighting in Gaza, which began 12 days ago, continues to stoke passions for weeks longer.

"There comes a point when duty becomes a factor," said a Western diplomat in the Middle East, speaking on condition of anonymity. "There's more a mounting pressure from the Arab street, and Hezbollah are the leaders of the Arab street."

Mitri, the Lebanese government official, said, "The more there is a delay in acting, the greater is the anger and the more significant is the radicalization of hearts and minds, the more there is a chance of spillover of the violence."

Hezbollah might also reconsider its militarily passive stance, analysts say, if it feared Hamas was about to suffer a catastrophic defeat that would irreparably harm the Palestinian national cause and change the region's balance of power.

"The likelihood for opening up a front depends entirely on Hamas' performance," said Amal Saad-Ghorayeb, a Lebanese scholar who has written about Hezbollah and Iran. "If Hamas is defeated, the Palestinian cause would be in serious jeopardy. On ideological or strategic grounds, [Hezbollah] cannot allow Hamas to be toppled."

The mountain ridges of southern Lebanon, long a staging ground for Arab attacks into Israel, were largely under the control of Hezbollah and allied militias during the 2006 war with Israel. Since that conflict, the Lebanese army and a bolstered United Nations peacekeeping force of about 13,000 international troops patrol the area south of Lebanon's Litani River, making it tougher for Hezbollah to launch rockets into northern Israel. U.N. officials describe the situation so far in the south as "stable."

But neither the U.N. force, known as UNIFIL, nor the Lebanese army is taking chances. They've stepped up patrols in recent weeks, largely in response to the discovery late last month of a cache of Katyusha rockets aimed at Israel.

"The regional situation might change at any moment," said a Lebanese military official, speaking on condition of anonymity. "The Lebanese army, along with UNIFIL, have taken all the necessary measures to deal with every step at a time."

In addition to worrying about Hezbollah, Israel is concerned that Palestinian groups based in Lebanon could try to launch an attack on northern Israel. "There is always the possibility that Palestinian militants, some of whom are overtly hostile to Hezbollah, will manage to pull off something, or be permitted to pull off something that is eminently deniable by Hezbollah," said Augustus Richard Norton, a former UNIFIL peacekeeper who teaches at Boston University.

The Israeli military has deployed reservists to the north and warned against attacks by Hezbollah or its allies. "I can only estimate that Hezbollah, along with the Iranians, are concerned by the massive blow Hamas suffered, fearing it might mark the first domino to knock down the narrative of resistance," Israel Defense Forces spokesman Brig. Gen. Avi Benayahu told Israel's Army Radio on Monday.

If the leadership of Hezbollah and its patrons in Tehran begin to believe that defeating Hamas was a prelude to a wider war meant to halt Iranian influence in the region, they might feel compelled to act sooner rather later, said Saad-Ghorayeb, a professor of political science at Lebanese American University.

"If Israel were to finish off Hamas, you can bet it would be emboldened to turn its sights on Hezbollah," she said. "Hezbollah believes this conflict is very crucial. The stakes are very high for all of Hamas' allies."

Hezbollah has made quiet preparations. One south Beirut resident said many of the Hezbollah militants living in his neighborhood had traveled south.

"Today it's Hamas, tomorrow it's Hezbollah," Nasrallah told followers Wednesday. "You cannot finish Hamas. You cannot finish Hezbollah."

Some who witnessed massive destruction in their neighborhood in 2006 and have experienced the slow, expensive reconstruction efforts since are nonetheless ready for a new war in support of Hamas.

"We Lebanese have strong hearts," said Ahmad Khiami, 21, a college English major with ties to the Hezbollah-allied Amal party. "I think there are many wars in the future between us and Israel."

The 2006 war also began during an Israeli offensive into Gaza, when Hezbollah kidnapped two Israeli soldiers and killed eight others as it fired rockets into northern Israeli in a major border incident. Israel responded with a devastating month-long air and ground offensive that destroyed Hezbollah strongholds in south Beirut and southern Lebanon. Still, many analysts inside and outside Israel say Hezbollah came out the winner because it survived intact. More than 1,000 people were killed in the fighting, mostly Lebanese civilians.

Mitri, the Lebanese Cabinet minister, acknowledged that even the presence of tens of thousands of soldiers in the south conducting stepped-up patrols could not prevent a war. "Maintaining stability in the south has nothing to do with the number of troops," he said. "It has to do with the political will of the parties involved."