Israel invaded the country for the first time in 1978 in response to a Palestinian Liberation Organization terrorist attack outside Tel Aviv, carried out by militants based in Lebanon. The war was followed up by a much larger invasion in 1982, an occupation of southern Lebanon until 2000, then another invasion in 2006. It was the last invasion that weighed heaviest on Israel during its current invasion of the country.

The lead up to 2006

Even during times of prosperity, the Lebanese government has been extraordinarily fragile, crippled by sectarian tensions between the Maronite Christians, Sunni Muslims, Shiite Muslims, Druze, and other Christians. The country was plagued by an inability to absorb or deal with the sudden influx of Palestinian refugees in 1948 and then 1971, when the PLO was kicked out of Jordan. That helped ignite a devastating, complicated civil war with shifting allegiances that wrought havoc from 1975 to 1990.

The PLO took advantage of the collapse of the central government to base itself in southern Lebanon, using it as a staging ground for attacks against Israel. Israel’s first invasion in 1978 was relatively brief and resulted in an Israeli victory.

Four years later, Israel launched its largest invasion to date, marching to Beirut to destroy the PLO, force a Syrian withdrawal, and install a friendly Maronite government. Though the PLO was defeated and forced to withdraw to Tunisia, Israel’s international credibility took a massive hit. International opinion turned against Israel over its Siege of Beirut, with then-President Ronald Reagan describing it in a phone call to Israeli Prime Minister Menachem Begin as a “Holocaust.”

The invasion ended in catastrophe after the assassination of the newly elected Israeli ally, President Bashir Gemayel. In the chaotic aftermath, an Israeli-allied Christian militia murdered thousands of Palestinian civilians in the Sabra and Shatila Massacre, prompting the intervention of the United States, the United Kingdom, Italy, and France.

The departure of the PLO also led to a power vacuum filled by a much more potent force: Hezbollah. The Iranian Islamic Revolution-inspired group drew on the support of disenfranchised Shiites, mainly based in the south, to launch attacks against American and Israeli forces. Increasing attacks from the group resulted in the withdrawal of the U.S. and other Western forces in 1984 and Israel in 2000. With the Lebanese Civil War concluding in 1990 with a Syrian occupation and disarming of most militias, Hezbollah became the most powerful armed organization behind Syria and Israel, significantly more powerful than the Lebanese government itself.

Following Israel’s withdrawal from south Lebanon, Hezbollah and Israel engaged in a low-level conflict for the next six years.

Then came the war

According to author Augustus Richard Norton, the 2000-2006 Israel-Hezbollah border conflict followed a set of unsaid “rules of the game,” with the two launching minor attacks that would be responded to reciprocally. Developments beginning in 2005 changed both sides’ calculus.

For Hezbollah, growing calls from non-Shiite Lebanese to disarm after Syria’s withdrawal led to a growing sense of dishonor and eagerness to justify its purpose as the only force able to combat Israel. Uncovered communications between Hezbollah and an ascendant Hamas, fears of its growing missile arsenal, and increasingly belligerent rhetoric from Hezbollah leaders resulted in a major shift in Israeli leadership circles. By the time hostilities broke out in 2006, “both sides were clearly itching for a fight.”

On July 12, 2006, in what Hezbollah leader Hassan Nasrallah later admitted was a major miscalculation, Hezbollah militants crossed the border into Israel to attack an Israeli patrol. Three Israeli soldiers were killed and two were captured in the initial attack. A rescue operation led to the deaths of another five, including the destruction of a prestigious Merkava tank.

The next day, Israel launched a full-on offensive into southern Lebanon, looking to eradicate the “cancer” of Hezbollah, in the words of then-Israeli Ambassador to the United Nations Dan Gillerman. After Oct. 7, 2023, Israel was able to ride a wave of international support, including from several Muslim Arab states.

Israel’s strategy broadly mirrored that of the 2024 invasion. It aimed to create a “killing box” by cutting off the supply lines and avenues of escape for Hezbollah fighters from its stronghold in the south, intensively bombing roads, seaports, and airports across Lebanon. Bridges over the Litani River were destroyed. Missile arsenals and suspected Hezbollah command and control centers across the country were bombed. Aiming for a decisive confrontation with Hezbollah militants, Israel attempted to evacuate civilians south of the Litani River by destroying supporting infrastructure, according to Norton, sending the populace fleeing north.

Israeli artillery and air strikes pummeled targets all across Lebanon, while air and naval forces instituted a total blockade of the country. Israeli Prime Minister Ehud Olmert blamed the Lebanese government for the outbreak of hostilities, given Hezbollah’s position within the ruling government. Despite this, the Lebanese government and army retained neutrality throughout the war.

The Israeli Air Force proved its effectiveness in the opening moves of the war, destroying the vast majority of Hezbollah’s long-range missile arsenal in 35 minutes on the first day, Israeli military researcher Avi Kober wrote in a report for the Journal of Strategic Studies. Significant parts of the Hezbollah stronghold of Dahiyeh, a Beirut suburb, were leveled.

Problems emerged for the Israeli military when the ground forces invaded. Israel had not fought a major ground war in over 20 years, with its troops primarily trained for policing operations to deal with the two intifadas in the West Bank and the occupation of southern Lebanon.

“For the last six years, we were engaged in stupid policing missions in the West Bank,” one reservist told a reporter. “… Checkpoints, hunting stone-throwing Palestinian children, that kind of stuff. The result was that we were not ready to confront real fighters like Hezbollah.”

Hezbollah fighters, acquainted with the land, moved from positions via an extensive tunnel network, firing on Israeli troops before retreating. Ambushes with advanced anti-tank missiles were set up in the valleys of south Lebanon.

Israel was also shocked when Hezbollah hit the Israeli Navy’s flagship, the INS Hanit, with a Chinese anti-ship missile, killing four sailors. Israel was not previously aware that Hezbollah possessed such capabilities.

An analysis from the U.S. Army Combined Arms Center’s Combat Studies Institute detailed Israel’s numerous tactical shortcomings during the invasion.

In one particularly egregious example, the Aug. 11-13 Battle of Wadi Saluki, Hezbollah fighters pinned down an unsupported tank and infantry brigade after disabling or blocking the first and last tanks in a narrow valley. Unable to move, the rest of the column was peppered with anti-tank guided missiles, mortar, and small arms fire, killing or wounding a large number of Israeli soldiers.

By the end of July, the Israeli military came under blistering fire from both international and domestic sources. An Israeli state-owned media company denounced its “idiotic military maneuvers,” while others questioned the army’s decision process. An airstrike against the town of Qana on July 30 killed 28 Lebanese civilians, decisively turning international opinion, especially that of Muslim countries, against Israel.

Israeli commanders noted the poor discipline of their troops, especially the reserves, and hesitated to commit more troops to battle. Three weeks in, 10,000 Israeli soldiers had only been able to advance 4 miles. In 1982, it had taken slightly over a week for Israel to cover the roughly 40 miles to Beirut.

With a looming U.N.-supported ceasefire, the Israeli government attempted to blitz through the south to the Litani River, resulting in disastrous encounters such as the Battle of Wadi Saluki. Soldiers and lower-level commanders complained of contradictory and confusing orders, resulting in a sluggish advance vulnerable to ambushes. An Israeli air assault deployed troops just south of the Litani River, at which point they were immediately surrounded by Hezbollah fighters. They were saved from catastrophe by the ceasefire.

Though it identified most long-range missile stockpiles, Israeli intelligence failed to appreciate the scale of Hezbollah’s short-range rocket capabilities. In the monthlong war, 3,790 Hezbollah missiles were fired into Israel, with the largest barrage symbolically occurring in the final hours before the ceasefire took effect. The missile attacks hit major Israeli cities, killing dozens of civilians.

What was learned

Israel experienced the worst casualty ratio in its history: 114 Israeli soldiers were killed, compared to around 184 Hezbollah fighters. Over 10% of the 400 tanks sent into Lebanon were damaged or destroyed. Over 1,100 Lebanese civilians were killed. Despite firing more rounds and launching more airstrikes than the much longer 1982 invasion, civilian casualties were significantly lower.

Israeli leadership and analysts widely viewed the war as a disaster. In the immediate aftermath of the war, Mossad Chief Meir Degan and Shin Bet head Yuval Diskin told Olmert in no uncertain terms that “the war was a national catastrophe and Israel suffered a critical blow.”

Israeli Air Force campaign planner Ron Tira gave a damning assessment, saying Israel had failed at all its objectives.

“Israel failed on the strategic, operational, and tactical levels,” he said. “Israel did not succeed in generating decapitation, paralysis, blindness, or any other effect that substantially harms the will or functioning of the organization’s command and control echelon. Nor did it succeed in suppressing the operational effectiveness of Hizbollah’s combat groups and light surface-to-surface rocket formations. At the end of the day, Israel did not upset the equilibrium of Hizbollah’s system and did not create a sense of helplessness and distress, nor did it push the organization towards cognitive-strategic collapse and a drive to end the war immediately on Israel’s terms.”

Meanwhile, Hezbollah, though its reputation was greatly bolstered, walked away from the conflict with a bitter taste. The cost to rebuild Lebanon amounted to $4 billion, a sum the dysfunctional Lebanese government did not have. Nasrallah later admitted that if he knew what the Israeli response was going to be, Hezbollah would not have carried out the kidnappings that triggered the war. The destruction wrought by the invasion contributed significantly to Nasrallah’s calculus to largely avoid an all-out war against Israel during the current war.

Reports indicate that the 2024 offensive into Lebanon is much better planned and more successful than the last, with the Israeli military taking a more cautious approach this time around. Critically, Israel spent the last 18 years building up an unsurpassed intelligence network within Hezbollah. The network’s effectiveness was illustrated by the assassination of Nasrallah and the pager and walkie-talkie attacks.