Yesterday was a painful anniversary (check the date) which should serve as a caution against direct US military entanglement in an Israeli cross border conflict. Seeing the current generation of Golani infantry on the weekend receiving a motivational speech evokes their engagement during the Siege of Beirut. Another episode in which civilians were trapped by the IDF.
Even after the PLO were expelled from Lebanon (eventually to Tunisia) Israel still went after them. Identifying at what point the situation in Gaza started to escalate is futile (Although Operation Cast Lead in December 2008 was an indication of Israeli intent).