Historians date the assault to 7 July 1980 (Ménargues, de Clerck and Malsagne, Hanf, Traboulsi, Picard). At dawn Bashir Gemayel's units struck National Liberal offices and barracks throughout the Christian region, the Safra Marine resort north of Jounieh among them, under strict orders to spare Camille and Dany Chamoun and their families. That evening he proposed merging the militias into the Lebanese Forces under his command; Dany Chamoun left for exile the next day. Estimates of the dead range from about 70 (Ménargues) to 150-200, mostly civilians (Traboulsi; de Clerck and Malsagne give about 150, including 83 Tigers). Ménargues says Bashir code-named the operation 'Altalena'.

Bashir Gemayel's pledge took the form of a letter to President Sarkis dated 6 July, which Sarkis never published (Ménargues).

Druze militiamen in Tibiyat, east of Beirut, visited by Fisk on 13 February, said the New Jersey's shelling of the Metn and Chouf foothills had killed 24 civilians and wounded 115 (their figures). De Clerck and Malsagne note the ship's frequent misses and its Arabic nickname 'New Jersa' ('new shame').