Final answer:
The U.S. sent troops to Lebanon in the early 1980s as part of a multinational force to stabilize the region after the Israeli invasion, which led to the 1983 Beirut barracks bombing and eventually the withdrawal of U.S. forces.
Step-by-step explanation:
In the early 1980s, the United States sent troops to Lebanon with the goal of restoring order following an Israeli invasion the year before. However, this intervention did not align with any support for the Palestine Liberation Organization (PLO) or retaliation against them. Instead, the presence of U.S. troops was part of a multinational force and was aimed at stabilizing the situation amidst the ongoing conflicts in Lebanon. This effort tragically included a barracks bombing in Beirut by Iranian-trained militants known as Hezbollah, leading to the loss of more than two hundred American servicemen and ultimately a withdrawal of U.S. forces in February 1984.