The Lebanese political crisis, triggered by Hezbollah's departure from government last week, has Israel worried that the situation could become violent and spill over the Israel-Lebanon border.

Regional efforts to mediate between Prime Minister Saad Hariri's bloc and the Hezbollah-led opposition failed today, with Turkey and Qatar giving up a day after Saudi Arabia pulled out.

The divide focuses mainly on whether Lebanon should participate in a United Nations tribunal investigating the 2005 assassination of Hariri's father, Rafik. The tribunal's first indictments are expected to target several members of Hezbollah, which has threatened to retaliate.

Israel is concerned that Hezbollah, which fought Israeli troops to a stand-still in a brief 2006 war, might stir tensions along the border in order to prove it is an indispensable line of defense against Israel – and thus gain the upper hand in the domestic stand-off.

"People are worried that things could get out of control,’’ says Eyal Zisser, a professor of political science at Tel Aviv University, "and that Hezbollah will want to divert attention from domestic problems in Lebanon, and the result will be an escalation on the border.’’

Israel unsure how to respond

The political maneuvering between Mr. Hariri, a Sunni politician backed by Saudi Arabia, and the militant Shiite movement Hezbollah is seen as highly combustible, because it is in effect a proxy battle between the allies of Western powers and those of Iran.

Israelis, still scarred by the toll of invading Lebanon in 1982 and 2006, see the sectarian tensions of its northern neighbor as a powder keg that could be exploited by Hezbollah and draw Israel into conflict again. Israeli leaders have portrayed the Iranian-backed Hezbollah as a forward command for Tehran, which could use the militia to fight a proxy war against its "Zionist enemy."

Israel is so worried about being drawn into the conflict that government spokespeople have remained uncharacteristically tight-lipped when asked to comment on their view of the situation in Lebanon. "We are following developments very closely,’’ says Foreign Ministry spokesperson Yigal Palmor, who declined to comment further.

That didn’t stop Foreign Minister Avigdor Lieberman, however, who called the Hezbollah resignations an example of "threats and extortion’’ to prevent the publication of an inquiry into the assassination, according to the Israeli news website Walla.

Would Hezbollah take aim at Israel again?

Some suggest that the Lebanese conflict could spin out of control, with some militant groups taking aim southward.

Other political commentators believe that a border clash with Israel would help Hezbollah persuade Lebanese that they remain their best defense against the Jewish state.) It could also help Hezbollah deter possible intervention by Western military forces, according to Alex Fishman, a military commentator for Israeli newspaper Yediot Ahronot.

Israel and Hezbollah fought an inconclusive six-week war in the summer of 2006. Though it was widely considered a victory for Hezbollah, many believe that Israel achieved a measure of deterrence because of the destruction wrought during the fighting.

"It is against Hezbollah’s interest [to attack]. At the current time it would be very difficult to explain why it would bring a Holocaust to Lebanon just because of its domestic political stress,’’ said Giora Eiland, a former Israeli general and national security chief in an interview with Israel Radio. "Because domestic legitimacy is important, that would not be correct.’’

Would Hezbollah try to take over Lebanon?

Though Israel already considers Hezbollah the strongest military power in Lebanon, many worry that the Iranian-backed group may one day completely take over its northern neighbor. Many Israelis also recognize, however, that Hezbollah might not want the headache of formal control.

"They will have to take into account the other communities, like the Sunnis and the Christians, who will not be happy,’’ says Moshe Maoz, a professor of political science at Hebrew University in Jerusalem. "I don't know if Syria would like to see Lebanon turn into a Shiite state because it is Sunni and secular.’’