Lebanon's army is trying to do what Israel failed to accomplish in its 1982 invasion of that nation. That is to drive the PLO guerrillas and terrorists out of southern Lebanon. But the motives are different. Israel wanted to stop raids from across the border, and punish those who commit them. The Lebanese government of President Elias Hrawi wants to reclaim Lebanon's soil, end the fragmentation that ensued from the 1975 civil war and restore Lebanese sovereignty.
That should provide no problem for Israel, which never had a problem with a Lebanon that was truly independent. But behind the Lebanese government stands its protector, President Hafez el Assad of Syria. His intentions are not clear.
Lebanon's reconstituted army has driven the PLO from military bases and into refugee camps near Sidon. More PLO fighters are further south, near Tyre, as reportedly are units of Hezbollah, the pro-Iranian terrorist group. Only when the army has cleaned them out will it face the moment of truth. That would be disarming Israel's Christian Lebanese proteges in the South Lebanon Army. And then it would mean barring Lebanese soil to Israeli armed patrols and listening posts.