Final answer:
The American intervention in Lebanon ended in February 1984, following the withdrawal of troops ordered by President Reagan after the tragic bombing of the U.S. marine barracks in Beirut by Hezbollah.
Step-by-step explanation:
The American intervention in Lebanon began in 1958 and saw another significant involvement in 1983 during the Lebanese Civil War. In 1958, the intervention was under the Eisenhower Doctrine with the deployment of fifteen thousand troops to support the Christian president Camille Chamoun against political opponents.
This presence was short-lived, as troops remained for only three months.
However, the most notable and impactful American military presence took place during the Lebanese Civil War, which began in 1975. The United States, under President Reagan's administration, sent forces to Lebanon in 1983 as part of a multinational peacekeeping effort.
This intervention took a tragic turn with the bombing of the U.S. marine barracks in Beirut by Hezbollah, which led to the death of over two hundred troops. As the situation in Lebanon intensified, President Reagan decided in February 1984 to withdraw U.S. troops, marking the end of American intervention in the country.