Throughout the latter half of the 1970s, Lebanon had been embroiled in a civil war. Beginning in 1974, Lebanon's Muslim population, supported by the PLO, had been fighting Lebanon's Christians for control of the country. In June 1976, Lebanon's president requested Syrian intervention. Syrian troops occupied much of the country. When the Syrian presence failed to stop the fighting, the Syrians began arming the Christian militias. In October 1976, the Syrians accepted an Arab League mandate to keep 40,000 peacekeeping troops in the country.
While the fighting among sects continued, the PLO launched terror attacks into Israel, prompting Israeli retaliatory attacks on several occasions. At one point, Israel occupied Lebanon south of the Litani River. When Israel withdrew to a southern Lebanon security zone twelve miles wide, the UN deployed a force (UNIFIL) to keep peace in the area.
In August 1981, Prime Minister Begin and Defense Minister Ariel Sharon began to discuss a plan for an invasion of Lebanon. The objectives would be to attack PLO targets as well as to assist Bashir Gemayel in becoming president of Lebanon. At the time, there was a ceasefire in place, and the PLO in Lebanon, while growing stronger militarily, offered few provocations from Lebanese territory. The PLO did, however, launch attacks from Jordan as well as attacking Jewish and Israeli targets in Europe. Israel responded with air strikes into southern Lebanon.
On June 3, 1982, terrorists attempted to assassinate the Israeli ambassador in London. Although Iraq was suspected in the attack, Israel retaliated with attacks on PLO targets in West Beirut and southern Lebanon. The PLO responded with rocket and artillery fire into Israel. On June 5, the UN passed a resolution calling for a cessation of hostilities.
On June 6, 1982, Israel launched Operation Peace for Galilee. The Israeli Defense Force quickly moved 40 miles into Lebanon, reaching the outskirts of Beirut. The Israelis swiftly cut the road between Damascus and Beirut, essentially cutting off the PLO forces from aid by Syria. Syrian aircraft did attempt to halt the invasion, but suffered heavy losses at the hands of the Israeli Air Force.
The Israelis found massive tunnels near the border. These tunnels were stocked with an impressive arsenal of weapons, from rifles to tanks, mostly of Soviet manufacture. Captured documents revealed that the Soviet Union both equipped and trained PLO terrorists.
The UN passed a second resolution calling for an Israeli withdrawal on June 6. On June 8, the US vetoed an additional resolution demanding an Israeli withdrawal. The US also called for a PLO withdrawal from Lebanon. On June 26, the US vetoed another resolution that would have preserved the PLO as a political force.
Israeli aircraft and artillery attacked PLO forces inside Beirut for the next several weeks. On August 12, the sides agreed to a truce, negotiated by the US, which called for the withdrawal of both the PLO and Israel. A multi-national force made up US, Italian, and French soldiers would keep the peace and protect Lebanese civilians.
The Israelis believed that many PLO fighters were hiding in refugee camps near Beirut. This led to the tragic case of Sabra and Shatila. On September 16, 1982, Israeli troops entered West Beirut, violating the ceasefire, and transported 200 Phalange militiamen to two of the camps. The militia members remained in the camps until the morning of September 19 and killed somewhere between 700 and 3,000 Palestinians.
Israel set up the Kahan Commission to investigate the killings and, by Israel's own admission, none of the dead were members of any PLO unit. The commission held Ariel Sharon and Chief-of-Staff Rafael Eitan indirectly responsible and recommended that Sharon resign. Sharon did resign, although he remained influential in the Israeli government.
On May 17, 1983, Israel, Lebanon, and the United States signed an agreement ending the war. The agreement called for the removal of Israeli and Syrian troops. The Arab world viewed the agreement as a surrender. Syria refused to withdraw, but Israel withdrew its forces back to the security zone in August 1983, where they remained until 2000. Syrian troops remained in Lebanon until 2005.
On April 18, 1983, a suicide bomber attacked the US embassy in Beirut. The US responded with a naval bombardment of Druze militia positions. On October 23, 1983, a second suicide bomber attacked the US and French headquarters killing 241 US Marines and 58 French soldiers. This sparked a series of terror attacks and kidnappings of Americans that plagued Lebanon for the remainder of the decade. US troops left the country in 1984.
Also during this period, the situation in Lebanon deteriorated into civil war again. Violence flared between the various Christian and Muslim sects and the Syrians. The conflict continued until 1990, when Syria launched a major offensive that secured the country.
During the late 1980s, disaffected Shiites from a number of groups banded together to form Hezbollah. This new terror group gained the support of Iran and quickly became powerful. It would soon become a dangerous foe of Israel.