What was the purpose and outcome of Israel's 1978 invasion of Lebanon?

Israel invaded Lebanon in 1978 with the primary goal of wiping out the PLO, which had been conducting cross-border attacks from Lebanese territory. The invasion successfully achieved its short-term objective of temporarily suppressing the PLO as Israel drove deep into the country from the south. However, the operation had significant humanitarian consequences, displacing hundreds of thousands of local residents, most of whom were Shia Muslims. After completing its military objectives, Israel eventually withdrew its forces following a United Nations resolution, though the regional tensions remained unresolved.