In reality, the invasion of Lebanon used the ANO assassination as a pretext, and this was fairly clear to Israelis even at the time. Israel's Prime Minister, for example, said simply that "they are all PLO", and Chief of Staff Rafael Eitan said "Abu Nidal, Abu Shmidal, we have to strike at the PLO". This stemmed from the general Israeli anger at PLO actions up to that point, and Israel had planned to invade Lebanon months earlier to strike at the PLO in retaliation for their infiltrations into Israel, and also to establish a buffer zone rendering their short-range rockets useless. Israel also had the goal of establishing a friendly government to itself in at least part of Lebanon, which was ambitious to say the least. This was not something Israel alone had a history of doing, as even Egypt's Sadat had previously used killings that seemed to be ANO-doing to criticize the PLO, at one point in 1978 calling them "pygmies and hired killers" despite the killers of Yusuf al-Siba'i (editor in chief of Al-Ahram, Egypt's leading daily paper) apparently belonging to the ANO.

In short, the goal had always been an invasion of Lebanon, and the ANO attack was used as a pretext. This was not because Israel lacked pretexts to begin with; despite the ceasefire for the few months prior, there was a long history of PLO attacks on Israel from Lebanon, as well as a continuing threat and geopolitical opportunity for Israel to be gained by invading (if it could succeed).