First Lebanon War

Israel invaded Lebanon on 6 June 1982, in Operation Peace for Galilee, after years of attacks by the PLO from Lebanese territory, especially rocket and artillery fire on northern Israeli communities; the immediate trigger was the shooting of Israel's ambassador in London, Shlomo Argov, on 3 June. The goal was to push PLO forces away from Israel's border and destroy their military infrastructure in southern Lebanon.

From Israel's view, the war began as an effort to protect civilians in the north. However, it became controversial when the army advanced far beyond the declared 40-kilometre line to besiege Beirut, forcing Yasser Arafat and some 11,000 PLO fighters to leave for Tunisia and other countries in August 1982, and Israel became deeply involved in Lebanon's internal conflict. The massacre at Sabra and Shatila by Lebanese Christian Phalangist militiamen in September 1982 led to the Kahan Commission and Ariel Sharon's resignation as defense minister, and Israeli troops remained in a southern security zone until May 2000.