From 1981 onward, the Reagan administration feared that conflict between Lebanese factions backed by Syria and Israel, along with clashes between Israel and the Palestine Liberation Organization (PLO), could escalate into an Arab-Israeli war. Yet American policymakers differed over how to prevent such a conflict, especially over whether to commit troops for that purpose. Following Israel’s 1982 invasion of Lebanon, the advocates of military intervention won out. But by 1984, terrorist attacks, a lack of diplomatic progress, and congressional opposition led President Ronald Reagan to withdraw U.S. forces from Lebanon.