TEL AVIV — Hezbollah may have hurt Israel with last week’s bus bombing in Bulgaria, but the Lebanese terrorist faction faces an uncertain future as one of its main sponsors — Syria’s Assad regime — faces a serious revolt and weakening support from once Arab allies, according to analysts.

Still, no one is predicting the quick demise of Hezbollah. 

As has been the case throughout the Arab popular uprisings of the past 20 months, Israelis have viewed the turmoil gripping Syria with wariness. President Bashar Assad was no ally of Israel’s — the countries technically remain in a state of war — but the Syrian regime has kept its border with Israel mostly quiet for nearly 40 years under Assad and previously his father, Hafez Assad. 

“We don’t feel reassured that those who are trying to topple the Assad regime are a great improvement,” said Zalman Shoval, a former Israeli ambassador to the United States. The Assad government, he said, “for its own interests, kept the armistice” with Israel.

Some Israeli policy experts, however, are looking forward to a Syrian regime change because it is one of Hezbollah’s main backers, along with Iran. Syria has acted as a crucial pipeline for Hezbollah to receive money and weapons from Iran and elsewhere.  A new Syrian government might close that route.

“Hezbollah is losing support in the Arab world,” said Shlomo Brom, a former chief of the strategic planning division of the Israel Defense Forces. “It’s on the wrong side of history. Syria was a central source of support.”

Hezbollah, however, remains a serious danger on several levels. 

In an address at an IDF ceremony on Sunday, Defense Minister Ehud Barak cautioned that Syria’s stockpiles of chemical and biological weapons may fall into Hezbollah control if they are transferred over the border due to a weakened Assad regime. 

“The State of Israel cannot accept a situation whereby advanced weapons systems are transferred from Syria to Lebanon,” Barak said. “There is no doubt that we are facing a global terror campaign, against Israel in particular, with Hezbollah at its center, inspired by Iran.”

Barak did not elaborate on the Israeli military’s plans. In a statement, the IDF said it “is carefully following events in Syria as they unfold, as they may have significant regional repercussions.”

Further, Hezbollah is now reported to have up to 50,000 missiles — more than three times the 13,000 it reportedly held when it began launching rockets at Israel six years ago, leading to the Second Lebanon War. In that nearly monthlong conflict, almost 4,000 missiles landed on Israel, killing 43 civilians and wounding more than 4,000. 

Israeli authorities also are worried about the security of the Israel-Syria border in the Golan Heights as Assad loses control of the country. Last Friday, Syrian rebels took control of several posts on the country’s borders with Iran and Turkey.

In May 2011, masses of Syrians stormed the Israeli border in commemoration of Palestinians losing their homes in Israel’s War of Independence, which they call the Nakba. More than a dozen people died as Israel fired on the protesters. 

Now analysts fear that a rebel takeover could lead to a porous border that allows terrorists to infiltrate the country. 

“The Golan may become a kind of Sinai, with ideological extremist organizations that are on our border,” Brom said, referring to the current state of Israel’s border with Egypt in the Sinai desert.

Regardless of the possible scenarios, the analysts all dismissed the idea that last the July 18 terrorist attack in Bulgaria was a direct result of the Syrian fighting. Senior Israeli government officials, including Prime Minister Benjamin Netanyahu, have blamed Hezbollah for the attack, which they say is the product of a global Iranian campaign of terror aimed at Israeli targets. 

Hezbollah and Iran have rejected the allegations.

Middle East professor Eyal Zisser said that “Bulgaria is a story with Iran and Hezbollah that is a long story,” while Barry Rubin, director of the Global Research in International Affairs Center in Israel, called the attack “part of the ongoing hidden war between Iran and Israel and part of Hezbollah’s ongoing effort to attack Israel.”

Shoval noted, though, that the attack in part could be Hezbollah’s way of asserting that it can survive without Syrian support. 

“Obviously there is a connection between what happened in Bulgaria and the situation in which Hezbollah finds itself these days,” he said. “Maybe it wanted to prove that it can also act indirectly or directly with Iran, and not only through the intermediary of the Syrians.”

But Shoval said that Israelis should not necessarily rest assured that Assad’s fall means Hezbollah’s decline, even though Hezbollah is a Shiite group while most Syrians are Sunni. 

“This is presented as a Sunni-against-Shia struggle, but with regard to terrorism and enmity against Israel, they won’t have any difficulty to cooperate,” he said. “One can’t rule out the possibility that Hezbollah will be supported by a Sunni regime in Syria.”

While most Israelis are worried about what Syria will look like when Assad falls, others are more optimistic. 

“In the Middle East there is a struggle between extremist Islam and moderate Islam,” said Alon Liel, who has advocated in the past for an Israel-Syria peace agreement. “In the long run, moderate Islam is not bad for Israel.”