In June 1982, the Middle East's most powerful military apparatus, the army of the State of Israel, swept into Lebanon in an operation called ‘Peace for Galilee’. As Israeli tanks rolled ever northward, straight through the 40-kilometre limit the Israeli government had originally defined for the operation, heading for the Lebanese capital, Beirut, Israeli leaders spelled out that their principal aim was to destroy the political and military infrastructure of the Palestinian Liberation Organisation (PLO), which had had its unofficial headquarters in Beirut since 1971. They explained that with the PLO ‘terrorists’ out of the way, they then hoped to be able to impose their own extremely limited form of political settlement on the Palestinian communities in the occupied West Bank and Gaza areas.

By mid-August, the PLO fighters in Lebanon and their local Lebanese allies had successfully repulsed several apparent Israeli attempts to capture Beirut; and despite many near misses, no member of the PLO's top leadership had been wounded or killed there. But civilian losses from the relentless Israeli air, sea and land raids against Beirut, as well as from the total blockade the Israeli army imposed around it, were running so high that the PLO leadership agreed -after receiving strict guarantees from the Lebanese and U.S. governments for the safety of civilians left behind – that the PLO fighters should evacuate the city.