More than a week into Operation Cast Lead, with what began as Israeli airstrikes on Gaza escalating into a ground war, Israel's border to the north remains quiet.
That frontier erupted in 2006, when another Israeli operation in Gaza, one to recover captured soldier Cpl. Gilad Shalit, escalated as a Hezbollah cross-border raid turned into a messy monthlong war.
The consensus in Lebanon has been that this time around, Hezbollah won't join the fight with operations in northern Israel.
"The main question was whether there was going to be a hot front here. It seems pretty clear that won't happen, and that's a relief," said Paul Salem, the Beirut-based head of the Carnegie Middle East Center.
But the second stage of Cast Lead, launched Saturday, renews the chance of Hezbollah coming into a broader conflict.
Amal Saad-Ghorayeb, a political science professor close to Hezbollah, says the group sees the ground invasion as a new phase in the fighting and in its potential involvement. On Sunday, local media reported that Hezbollah militants have been put on "high alert."
"We shouldn't overestimate Hezbollah's restraint. ... At this stage, if Hezbollah is provoked in any way, even a small incident, it could give Hezbollah the justification and pretext to enter the conflict," Saad-Ghorayeb said.
Some analysts see Hezbollah holding back, in part to maintain its political advantage at home. Though Hezbollah has its critics in Lebanon -- above all, its rivals in the anti-Syrian March 14 coalition -- Hezbollah now leads a broad-based coalition that is politically well positioned for this year's Lebanese elections.
Hezbollah, a terrorist group in the eyes of America, Israel and much of the West, could -- together with its allies -- win a majority of seats in parliament.
"At this point it's neck and neck, but they are a dominant force in Lebanon," Salem said. If Hezbollah launched an attack on Israel now, it would risk undermining its cross-sectarian support.
Hamas: A Hezbollah Partner and Pupil
Saad-Ghorayeb describes the relationship between Hezbollah and Hamas as a mix of partner and pupil.
"Hamas is learning from Hezbollah as a resistance model. They are close partners with a very close relationship, but it is one where Hamas is clearly autonomous," she said.
What Hamas has learned reflects Hezbollah's strengths: its hallmarks of indiscriminate rocket fire and guerilla warfare.
"Hezbollah is very optimistic that Hamas would perform well in urban warfare," said Saad-Ghorayeb, who believes Hezbollah has trained Hamas in urban fighting tactics. Hezbollah's confidence that Hamas would do well against Israeli ground forces is another reason analysts say Hezbollah has not joined the battle.
Sunni Hamas and Shiite Hezbollah share an ideology and a set of strategic goals that have superseded their religious difference. Both groups were founded on the fight against Israel and their alliance, along with the support of Iran, has accelerated the buildup of Hamas' firepower and fighting tactics.
"Israel is discovering that [Hamas] capabilities are much more sophisticated than they expected," said Dan Senor, a Middle East expert with the Council on Foreign Relations. Senor believes Hamas has gained tremendously from its ties to Hezbollah and Iran.
"Hamas would never have been able to launch a rocket into Beer Sheba had it not been for Iran," he said. "That puts a much larger range of the Israeli population within reach of Hamas."
By Senor's count, using the rockets into Beer Sheba as an indicator, Hamas rockets can now reach up to 700,000 Israeli civilians.
"It's very discouraging, obviously, though Israelis would argue it's very vindicating. It vindicates their decision to take action," Senor said.
Tony Cordesman, a security expert with the Center for Strategic and International Studies, says both Hamas and Hezbollah require "fighting a very asymmetric war. Israel has to use conventional military means to defeat an opponent that is more an ideological one than a military one."
Syria, another player in the Hamas-Hezbollah partnership, has shown a mixed record in the last years. At one point expelling Hamas political chief Khaled Meshaal and opening indirect talks with Israel, Syria has poked holes in what some Western observers had seen as an intractable alliance.
"This is a region in which everyone tries to use everyone else. There can be quick division toward their own interest," Cordesman said. "But certainly we have seen an alliance between Iran, Syria and Hezbollah that has changed the security equation in the region."
In other words, Saad-Ghorayeb said, "each one stands to benefit from the victory of the other."
An Old War's Wins and Losses
The victory Hezbollah often cites -- one that Hamas is now using as a model for its operations -- is the perceived win of 2006.
"Hezbollah has used its ability to survive, what it sees as victory, as leverage," said Cordesman, the security expert.
In November, Israeli Defense Minister Ehud Barak told Israeli officials that Hezbollah had tripled its weapons stockpile. In a little more than two years since the Israeli-Hezbollah cease-fire of 2006, he said, its arsenal has grown from 14,000 rockets to 42,000.
"Hezbollah can certainly carry out significant rocket launches against Israel, but whether it can do serious damage is another question. And Israel has reorganized, retrained its army, restructured its targeting and Air Force. The Israeli Defense Force has learned from experience," Cordesman said.
As Israel puts those lessons into practice against Hamas, Cordesman said, it gives rise to a new security risk. He and others say this is a fight Israel must win.
"If Israel doesn't very substantially achieve its goal, Hamas survives and this becomes the second war where Israel uses its military force but cannot achieve a decisive win, it undercuts the Israeli deterrent, or edge, in the region," he said.
Hezbollah has also had to account for gains and losses on its side.
With the deployment of UNIFIL troops and the Lebanese army after the war in southern Lebanon, Hezbollah lost some control over the border area.
While some analysts point out that the Lebanese army has strong links to Hezbollah and would support it in any fight with Israel, Carnegie's Salem believes the forces patrolling southern Lebanon have limited the launch of cross-border raids.
That limitation was one of Israel's primary achievements from the Second Lebanon War, as the 2006 conflict has been called. It sets a limited but critical objective for Israel's fight with Hamas.
"As dreadfully executed as the Second Lebanon War was, the Lebanese border has been basically quiet for the past two years. If the Israelis can get to a situation where the Gaza-Israel border is quiet for some time, I think that would be a small victory," Senor said. "If it is quiet for a long time that would be a huge victory."
Among Hezbollah's post-war gains, said Salem, is massive popularity in the Arab and Muslim world. In Lebanon, Hezbollah consolidated its base and formed a political coalition with Christian and Druze leaders, consolidating its position as the preeminent Shiite political force.
War of Words
So far, the battle Hezbollah has begun is one of rhetoric and rallying the Arab street. Sayyed Hassan Nasrallah, Hezbollah's secretary general, has made a series of speeches since the start of conflict, praising Hamas and attacking Arab states that have made peace with Israel.
"There is a permanent U.S.-Israeli project in the region. ... Some Arab regimes are partners in this project," Nasrallah said Friday.
Nasrallah has called out Egypt for special criticism, slamming its policy of a closed border with Gaza and urging Egyptians to protest their government.
"Hezbollah has never [before] singled out an Arab regime the way it has," said Hezbollah expert Saad-Ghorayeb, who sees the move as a paradigm shift.
"The strategy of Hezbollah is to put pressure on Egypt to weaken Israel," she said. "It's a goal toward weakening the Israeli support. Without Arab support Israel would be in a much weaker position."
Last week, as a Nasrallah speech played on video screens overhead, tens of thousands of Hezbollah supporters rallied in Beirut's southern suburbs. Across the Arab world crowds demonstrated against Israel, roused by the fighting and by Nasrallah's call.
"From the very beginning of Hezbollah's existence they've felt they were the spearhead of a movement against Israel," said Judith Palmer-Harik, a political scientist in Lebanon and author of "Hezbollah: The Changing Face of Terrorism."
"They feel themselves morally responsible for a position that denounces peace treaties and agreements signed between Israel and Arab governments. Most people in the Arab world believe that stance ... and that's responsible for much of Hezbollah's following," Palmer-Harik said.
That fighting in the Gaza Strip erupted during Ashura, a Shiite holiday that promotes the glory of martyrdom, sharpens Hezbollah's rhetorical point.
"The faithful fighter either achieves victory or falls martyr," Nasrallah said in a speech last week.
"In both cases, he wins."