Reagan was trying to get peace in Lebanon as we had troops there. Remember the Beirut Embassy bombing and Arafat. The April 18, 1983, United States embassy bombing was a suicide bombing in Beirut, Lebanon, that killed 32 Lebanese, 17 Americans, and 14 visitors and passers-by.
Essentially, we (USMC) were put in a UN peacekeeping force and sent to Beirut. We did not wear the baby blue helmets or UN patch (in fact, we were told that our arm would be removed by fire axe if we sewed the patch on LOL) We did not know our mission until we got there. Within a few days there, we found out it was to protect the PLO, including Stinky Arafat, from the IDF. They had started crap in jerusalem and the IDF chased them out over the lebanese border. Then the PLO started mortaring Israel from there. The IDF then warned them and mobilized to end the situation. They then chased the PLO northwards. I watched a lone Captain with a .45 step into the main highway and face down an IDF tank. The column turned around and headed south. They did not know that we did not have ANY ammunition at that point. It was all out on the ships in the med.