Yet even as Hezbollah has acquired dangerous new capabilities, Israel has confined itself to public criticism rather than military actions or cross-border invasions to disarm or weaken Hezbollah as it has done previously.
"The ability to hit Tel Aviv was a red line for Israel in the past, but now we are seeing the red line pushed a little farther," Atrache said. That might reflect Israel's fear about Hezbollah's ability to unleash thousands of rockets against its cities, she said.
Some see Iran as a factor in Hezbollah's more moderate approach along the Israeli border, saying Tehran is pushing Hezbollah to refrain from rocket attacks or military operations so that such retaliation can be saved for a later time, such as if Israel strikes Iranian nuclear facilities.
Israel has been using the recent calm on its Lebanese border to boost its defenses, particularly against rocket attacks. It hopes to soon deploy Iron Dome, a short-range rocket-interception system, and it completed a successful test last month of the Arrow system, designed to knock out ballistic missiles and expected to be operational by 2014.
Some experts say the lull won't last.
"The mutual deterrence has worked until now to prevent any casual escalation, but it won't last forever," said Daniel Kurtzer, former U.S. ambassador to Israel. "At some point red lines will be crossed, and if there's a situation in which either side believes its interests call for it, they'll take action."