1982 Lebanon War

The 1982 Lebanon War (Hebrew: מלחמת לבנון הראשונה‎, Milhemet Levanon Harishona, "the first Lebanon war"), (Arabic: الاجتياح‎, Al-ijtiyāḥ, "the invasion"), called Operation Peace for Galilee (Hebrew: מבצע שלום הגליל, or מבצע של"ג‎ Mivtsa Shlom HaGalil or Mivtsa Sheleg) by Israel, and later known in Israel as the Lebanon War and First Lebanon War, began on 6 June 1982, when the Israel Defense Forces invaded southern Lebanon. The Government of Israel launched the military operation after the Abu Nidal Organization's assassination attempt against Israel's ambassador to the United Kingdom, Shlomo Argov.

By expelling the Palestine Liberation Organization (PLO), the removal of Syrian influence over Lebanon, and the installment of a pro-Israeli Christian government led by Bachir Gemayel, Israel hoped to sign a treaty which Menachem Begin promised would give Israel "forty years of peace."

After attacking the PLO, as well as Syrian, leftist and Muslim Lebanese forces, Israel occupied southern Lebanon and eventually surrounded the PLO and elements of the Syrian army. Surrounded in West Beirut and subjected to heavy bombardment, the PLO forces and their allies negotiated passage from Lebanon with the aid of Special Envoy Philip Habib and the protection of international peacekeepers. PLO, under the chairmanship of Yasser Arafat, had relocated its headquarters to Tripoli in June 1982.

However, following the assassination of Bachir Gemayel, Israel's position in Beirut became untenable and the signing of a peace treaty became increasingly unlikely. Outrage following Israel's role in the Christian-led Sabra and Shatila Massacre of Palestinian refugees and Israeli popular disillusionment with the war would lead to a withdrawal from Beirut to southern Lebanon. As a result, Shi'a militant groups began consolidating and waging guerrilla war over the Israeli occupation of southern Lebanon, leading to 18 years of armed conflict. The Lebanese Civil War would continue until 1990, at which point Syria had established complete dominance over Lebanon.