How Iran and Hezbollah trapped Israel into staring down 150,000 rockets on its border that it can only counter at a terrible cost

• Israel this week sent more units to reinforce its northern border with Lebanon, which bristles with rockets and missiles from the Iranian proxy group Hezbollah.
• Tensions there threw light on a long-standing dynamic which Israeli sources told Insider is a trap their leaders effectively walked into.
• Over decades Hezbollah has augmented and reinforced positions on the border — now with some 150,000 rockets — that Israel's military would struggle to remove.
• Israel can neither accept the threat the weapons pose, nor commit to the expenditure and bloodshed required to clear them out — leading to an uncomfortable stand-off.

The Israeli Defense Forces this week moved specialized military units to its northern border to reinforce its increasingly tense outposts along the borders with Lebanon and Syria.

Israeli officials described it to Insider as the most significant build-up in years, prompted by fear of a major operation by Iran and its Lebanon-based proxy force, Hezbollah.

The movement shed light on Israel's impossible situation along its border with Lebanon, which bristles with as many as 150,000 rockets and missiles pointed at Israel.

To the Israelis, the build-up is an intolerable threat — but also one it can only remove with huge loss of life and capital, which it has thus far been unprepared to commit.

Israel has conducted scores of strikes against Iranian and Hezbollah positions in Syria and Lebanon since the outbreak of the the Syrian civil war eight years ago — but in historical terms the border has still been quiet. Hezbollah has been occupied helping its allies Iran and Syria defeat the Syrian revolution.

Insider's sources in Israeli defense circles fear this relative calm may be about to end.

"The Iranians and Hezbollah have laid a very dangerous trap for us in the north and I am not clear on how there can be a military solution to this crisis that would come at an acceptable cost," said a former senior Israeli official who remains closely briefed on Iranian projects in the region.

"It is militarily unacceptable that Hezbollah and Iran have 150,000 missiles and rockets pointed at Israel," said the official, who asked not be named as he was criticizing the current Israeli government on national security matters.

The source is referring to Hezbollah's three-decade-long program of developing hidden and protected missile and rocket launch sites throughout southern and eastern Lebanon that are nearly impossible to interdict with air strikes.

Hezbollah's leadership often says the rockets and missiles are meant to deter Israeli aggression against Lebanon.

The group can pour dozens if not hundreds of rockets into Israel settlements throughout the northern third of the country almost unimpeded. Larger, more advanced, systems are capable of hitting the entire country.

The former official said: "The IDF is not capable of conducting an operation in Lebanon to stop the rockets and missiles fast enough to avoid enormous political and economic damage."

"To do so would require an full-scale invasion of Lebanon that would send units deep into the Hezbollah 'Nature Reserves' to chase down individual launchers while also battling the group militarily.

(IDF members often refer to Lebanon's groups of underground bunkers as Nature Reserve.)

"This would lead to huge numbers of casualties on the ground as well and there's little reason to think the rockets could be stopped for weeks in this scenario.

"I'm not sure anyone could conduct this operation quickly enough to protect the Israeli people," the former official concluded.

In 2006, Israeli forces were stunned to realize that the group had turned most of southern Lebanon into hardened fortifications that could not be seen by air.

Avi, a former IDF intelligence official who asked to be identified only by his first name, said: "In 2006 it became clear that after the IDF withdrawal from Lebanon, Hezbollah had fortified the entire south and it would be foolish to think these defenses have not been substantially increased in the years since that fight," said.

"Hezbollah has designed its military capability very carefully and with a singular focus: As long as rockets are landing on Israel and the Israeli people are living in bunkers, Hezbollah is winning."

"Hezbollah's leadership believes it can take the pain of a conflict longer than Israel can and they are probably right."

He describe Israel's counter-strategy as having three parts:

• The threat that in a true escalation, Israel would attack the entire Lebanese state — a fixed target — rather than Hezbollah forces which are hard to pin down.
• High-tech solutions like the Iron Dome rocket defense system. It has worked well in Gaza, Avi said, but it is not clear that it could withstand far larger, sustained barrages that Hezbollah could produce.
• Occasional air strikes in Syria and sometimes Iraq, meant to destroy advanced weapons systems before Hezbollah's allies can get them to Lebanon. However, these strikes sometimes kill Hezbollah personnel and threaten to start a cycle of strikes and retaliation.

"It's a nice trap that the Iranians set for us, and I am afraid our leadership spent the last 30 years just blindly walking into it," said Avi, who worked in South Lebanon during the 1978 to 2000 occupation.

"This is why the most serious people in national security know that only negotiations with Iran over time can diminish this threat, in this case the Iranians and Hezbollah have established a level of deterrence that would have been unimaginable to the Israel of the 1970s."

Ironically, according to Avi, what had been keeping the situation in check was the extent of Iran's commitment to the Hezbollah project.

"Iran has spent billions of dollars and thirty years developing and supporting the Hezbollah model and the fruit of this effort is a strong deterrence that says if you hit Iran or its nuclear program, we can strike back and hit Tel Aviv and even maybe Israel's nuclear facilities," said Avi.

"But both sides know that an escalation like this can be threatened many times but used precisely once, as the next major war will be to the end of this problem. Iran did not develop this capability to use it lightly."