Begin’s pronouncements and Israel’s actions, as well as the peacemaking process, were soon overshadowed by other developments in the region. on March 11, 1978, a PLo terrorist unit landed on a beach in Israel and attacked and seized a bus filled with Israelis. The resulting firefight left 37 Israelis killed and more than 75 injured. It was against this background that 15,000–20,000 Israeli troops in a combined air, sea, and ground assault, entered Lebanon on March 14.
The declared objective of the operation was to direct blows at the terrorist organizations and to eliminate PLo bases and staging areas south of the Litani River. After initially securing a strip along the border between its territory and that of Lebanon, Israel continued to move northward and eventually occupied much of Lebanon south of the Litani River.
U.S.-sponsored United Nations Security Council Resolutions 425 and 426 were adopted on March 19. They called for an immediate Israeli withdrawal and the establishment of a United Nations Interim Force in Lebanon (UNIFIL) for the purpose of confirming the Israeli withdrawal.
Israel began a phased withdrawal from southern Lebanon on April 11, after a UN peacekeeping force entered the area to prevent infiltration by hostile forces from Lebanon into Israel. on June 13, the last Israeli troops withdrew.
Negotiations between Egypt and Israel, meanwhile, continued, but progress was minimal. The foreign ministers met at Leeds Castle, in England, in July 1978, with no significant advances. on July 23, Sadat asked for Israel to return portions of the Sinai to Egypt as a symbolic gesture. Begin refused, adding that “Nobody can get anything for nothing.” Sadat’s reaction was angry.
In a series of moves, he publicly denounced Begin, demanded evidence of greater Israeli flexibility, expelled the Israeli military delegation from Cairo, and declared that the peace talks could not resume until Israel provided some new element.In August, Carter sent handwritten invitations to the leaders of Israel and Egypt to come to the United States to meet with him at Camp David in early September. Both Begin and Sadat gave immediate and unconditional affirmative responses.